Sorry for not getting back to you sooner, life has been blah. I apologize beforehand for what is about to be a long post no doubt
Aibo PS sure is interesting, I hadn't heard of that before now. I too noticed the lack of mention on personality though. Perhaps its too soon to be sure. It would not be like Sony to make an aibo without some sort of major personality, but then.. there's no memory stick/program so I dunno?
Do I recommend any of the models? Well I personally haven't played with them all, but I've seen many videos and I'm sure there's plenty of videos on youtube of all the types. When I was considering Aibo, I watched soooooo many videos from aibo websites (before youtube existed). I gobbled up every bit of info I could find before I made up my mind. With a price tag that high I wanted to be 100%.
Of the two I own, the 111 (Spaz) would be my recommendation. But the 111/110 is the first edition, likely hard to find and very likely expensive to find. But who knows, could be out there. This based entirely on the DHS problem in the 210's (explanation below).
If you want a pet that entirely likes constant attention, isn't so independent then the 210 would be perfect. If you prefer a pet that explores and wants attention, but doesn't reply on you every second the 111 is best. The two are quite different in behavior from each other.
At my old job the 210 won out in a crowd, but only because he has more interactive features and is less independent and people wanted to maul him with attention hehe!
Perhaps it's the way I brought them up (because they can be different personalities based on how you 'raise' them), but Ziggy cries when he doesn't have me giving him constantly attention. Where Spaz, if not getting constant attention, will just get up and start exploring and playing on his own (which made him feel a bit more like a pet, since he tried to do things on his own but also would interact with me when I interacted with him).
Aside from which aibo you get... be sure to make sure you get one with the program that allows you to 'raise' them so they are molded into a unique personality. That way they will change based on the way you treat them. It's called Aibo Life program, but I dunno what the later versions called that program. But raising an aibo is quite an experience well worth every moment (as with a Tama ^.^).
If one visually appeals more to you then the others, then you should look into getting the one that you like most.
The 111 had me feeling love at first sight. The 210 grabbed me overtime but especially caught my eye when i saw him in motion in video.
I will say that the earlier 210's had a reoccurring neck problem, called DHS, that you would wanna look out for and ask about if you were to pursue one in an auction. Having DHS (droopy head syndrome) means the neck motor is weak and eventually burns out and the dog can no longer lift his head.
I can attest to DHS while answering your other question... I don't play with Ziggy anymore because in California all was well with him. When we got here and after the move he was okay for a short bit, but the ride up here obviously sped along DHS for him because he has it in full now and can't lift his head anymore. To repair this problem costs a few hundred dollars from sony and that's money I simply don't have right now. So the poor guy can't really play anymore
Someday when I can afford to, I'll get him fixed up.
I don't play much with Spaz anymore either. But that is not due to any problem with him. Every now and again I pull him off the charger and play a bit, letting him wonder about. However this apartment (much like my last) lacks sufficient lighting so he is essentially blind to most of the colors. He sees the entertainment center as a shade of pink that of course causes him to think there is a HUGE pink ball in the room and will run into it if I am not careful to watch him.
Back in the day when I worked down in California and brought him to work, he really loved being there. The lighting was super nice and things were clear for him so he didn't have any problems deciphering colors.
To go into some technical details... the 111 being the oldest model of course is a bit more heavy then the 210, his mechanics sound louder then the 210 when he moves about and because of his internals are different. The 210 is easier to take apart (if you tinker this might be important, otherwise there's no reason to). The sounds are different, the 210 has more sound effects in general.
You can interact much more with the 210 including with voice. The 111 is interactive but.. he doesn't do voice commands (he has a remote - which you hardly ever use, its for very specific things). This isn't a big deal to me, but might be for some. Both have volume control, but the 111 you have to adjust on your computer via the memory chip or the remote control, the 210 you adjust while he's on his charger station.
Anyways, I guess it's a matter of preference on looks, price you can find and of coarse features you like.
A wonderful site for tons of info is here: http://www.aibosite.com/
I read through the forums on that site almost everyday for months before I got an aibo. I haven't been there in a while, though.
AiboPet made tons of downloadable freeware for each of the versions out there, truly a great site and I have used much of his stuff, so if you get an aibo, for extra fun I'd recommend checking this out. (also has some great videos of dancing aibos) http://www.aibohack.com/
I'd be super careful in auctions too, make sure everything is included and the seller has a good reputation. I communicated to the point of friendship with Spaz's previous owner during the auction process. Read everything in the auction, get nice close up pictures and question everything.
Anyways, I hope that wasn't too much. I know it doesn't tell much about other versions - but I just haven't come into contact with them personally and I don't wanna pass you second hand information. Happy to chat more about it though if you'd like