I agree with what has been said above, esp what Crewella said, As far as personalty and charm, I think it is hard to beat a Ugobe or a 2009 Pleo, which is the improved version of the orginal Ugobe but with stronger cable wires in the neck and skin that is supposed to be better to having skin problems, such as peeling, cracking or paint problems.
I think untill you have had the original Ugobe or the updated 2009 Pleo, you do not fully appreciate the differences between Pleo and Pleo rb. To me Pleo wins hands down for simple charm.. and I LOVE them. Pleo will explore on his own and if you want to see the differences in Pleo and Pleo rb as far as walking, get a Pleo, they are great at walking and exploring, Also another charming function and difference between Pleo and pleo rb, is that Pleo, the original or in this case, the 2009 Pleo version, will sing on it's own without any learning stone ( like the one needed by Pleo Rb) or simply by rubbing under Pleos chin. They also have very nice singing tones, with not one, but three different sounds, with one reminding me of a cricket.
Pleo can also still learn "tricks" but without having to go out and by Learning stones. Pleos are just so much fun. If I had the choice of buying a Pleo RB or a Ugobe or 2009 Pleo and had none to start with, I would start with the 2009 Pleo, There is so much you can learn just by owning the 2009 Pleo, and you won't have to worry about setting a time clock in their foot, having them wake up and fall off a shelf, and they won't get sick if you don't feed them and they also will not be affected by too much heat or cold, They still can get sick, like a cold and it is nice to see them be nursed back to health, and one more caution, they still need to be kept out of extreme fluctuations in either heat or cold, simply to protect their skin esp from cracking or drying out. Best of luck, and let us know when you decide which Pleo to go for. You cant go wrong either way, but if I had never owned a 2009 Ugobe, I would go for it, Of course if you buy one and then decide you would rather have another Pleo Rb, you can always sell the 2009 Pleo here on the forums.. RWM and the Pleo township of the Redwoods