There are of course plenty of women who could be considered the 'best' for Don Lothario, but what about between these two? Do you think Dina goes better with Don than Nina does, or the other way around?

Nina most definitely.
They always seem drawn to each other. They are devoted to one another even though both are romance.
Have had them marry and have children before in previous games, the children are beautiful.
They are both wonderful doting parents as well.

I would definitely say Nina. In my game she was frequently Don's "one sim" (ACR), they dated a lot, often rolled wants for each other outside of dates and Don even rolled the want to marry her at one point! They are currently in an open relationship, but living separately, and it seems to suit them.

Nina. I agree with what the others say, plus Dina is just a gold digging, back stabbing biotch. Honestly though, in my game I usually have Don call off all the other flings with the ladies and make him marry Cassandra.

Nina, at the start of the game Don likes her significantly more than he does Dina. She seems to be the one Don cares for the most, actually.

Nina.
After Dina realizes that although Don is Chief of Staff and is bringing home the bacon, he doesn't ever want to move out of his bachelor pad, she loses interest and marries Mortimer. Though in most games Nina finds herself pregnant with Daniel Pleasant's child and ends up devoting a lot of her time to looking after him/her. She still goes on the odd date with Don, but she has to sort it around looking after her child - I always planned on making them have a love child but I just never got round to making it happen because soon after Don's second child he decided to stay faithful to his wife instead.

All in all, I prefer Kaylynn. In my game they often just fit together really well. She's good at taming him. They currently have two sons - Rocoe and Vito and last time I played them Kaylynn found herself pregnant again.

I don't think those two money hungry Sims Nina or Dina should be with Don period, I have never really care for neither one of them. In my game I created two of the most ugliest Sims and gave it to Nina and Dina as a gift of having them.

I just don't see either Dina or Nina with Don because Dina is Cassandra's aunt. That's just a little too soap-opera for me, even in a game that's all about the soap-opera. My thought is that Nina's thing with Don is past, and that's just a residual affection for a guy she used to hook-up with now and again. Don, on the other hand . . . well, he's got the morals of . . . a rooster, yeah, that's it. Nina and Dina have more integrity than that.

Hmm. Well, in my game, Dina always seems to roll Don wants, including getting engaged to him even when he is still engaged to Cassandra. And that want usually persists for a while, along with her 'Marry a Rich Sim' want. Basically, while Dina seems more hard-working (Nina doesn't seem interested in getting a job or advancing in one, ever), this also tells me that Dina seems more conflicted and has no idea what she actually wants! Nina, on the other hand, knows what she likes and just kind of does it, even though sometimes it is without regard for others (affairs with taken men or women really irks me in real life, so I personally can't think too highly of either of the Caliente twins, but they are complex and I think could be viewed and played from many angles, or even grow to change...)

But I think in that way Don meets his maker in Nina -- he always seems to like her better than Dina, and he seems to like Nina more than she likes him, too, an interesting dynamic for the town playboy And to me, she isn't playing hard to get, she just simply doesn't care if Don sees other women! I think this intrigues Don; most women fall head over heels for him and do anything for him, want him to commit..Dina falls in that category. For Don, I think Nina exhibits a sort of independence (though I would say she is just afraid of commitment at the moment :D). So, Nina would be my answer. She just seems more level-headed than Dina when it comes to Don, and I think that is what will tame Don eventually, if he is to be tamed.

Nina because I can't stand Dina at all.

Actually, I always end up killing both of them off or using the renuyu senso orb on them.

There's a ticking time bomb in my Pleasantview: Nina and Dina are both having passionate affairs with Don without telling the other. There's going to be hell to pay when they find out, and I'm not sure if the sisters will be able to go on sharing the same house. In the long run, I think Nina may well end up with Don. Peni has persuaded me that Dina is quite vulnerable, so I think I'll protect her from marrying Don. I'll try to fix her up with a nice rich townie. (Mortimer is back with Bella.) Nina and Don won't be a happy marriage either, but I think Nina is well able to give at least as good as she gets. She's mean, shy and serious -- precisely what you don't want in a Romance Sim if you have Pescado's Romance Mod. She'll expect fidelity from Don, even if she demands the right to flirt with every man she meets. I'm not sure how Don will handle that, but she'll demand perfection from him. All told, if they end up together, it will be a very stormy relationship unless one, or both of them completely change their ways.

Sisters share. :P

Dina because Dina is a golddigger and Don is a big asshole - perfect match

Nina, because Dina always tries to make do with Mortimer, because Mortimer is pretty damn rich... but Mortimer usually dies before Dina marries him, boohoo. At least you still get some of his shiny Simoleons in the mail!

Nina is pretty much Don's only love left, after being caught cheating on Cassandra, and after catching Kaylynn WooHoo with Daniel. Dina usually catches Nina making out with Don on the couch, so Don only has Nina left. Unless I move in some of my own Sims, then he has some more company...

Neither, because they all (including Don) deserve a fresh start.

Couldn't stand playing the Nina and Dina, until I deviated from the pre-made story and had them get lives of their own. It worked out for Don as well. He was finally free to be himself, after I stopped trying to pair him up with Nina, Dina or even Cassandra.

I started a new neighborhood not that long ago, and this time around I am not pairing up anyone that was previously meant to be together. By switching things up, I've had some fresh drama and quite a few unpredictable moments happen. So, I don't regret a thing.

Wait a second. Isn't Nina trying to get hitched with Mortimer Goth so she can get her hands on his money after he bites the dust? If that's the case, then clearly Dina is the perfect choice for Don, despite her however-numerous "quirks".

No you've got it mixed up, Dina is the one trying to marry Mortimer for his money. Nina is the other one, the redhead.

I prefer Nina out of the two, but Don is a cheating man-whore who doesn't deserve Nina, so I'll usually have him and Dina end up together in a twist of fate and Nina find some other suitor or realize she's lesbian.

The game starts out with Dina wanting to marry Mortimer, or just a rich Sim in general.

Ah, that's right. It's been a while since I had the Calientes pay Mort a visit. Danke.

Nina for sure. I had them become roommates because they were both romance sims with the same LTW (Woohoo with 20 sims), and I ended up just getting them hitched and starting a family. They would always spontaneously flirt and kiss. The cuteness was too much.