What others have said here is spot on. Just to add a bit more to the points.
I think the main thing about eclectus parrots is they are smart, learn well (and retain what they learn), and do have their own personalities. These I think are the major Pro's or Con's depending on your circumstances and commitment to sharing your life with an eclectus parrot.
My two are both adoptions (Gizmo and Pebbles), the major cons they had when they first arrived, I would now put down to the above 3 traits (smart, learn well, have personalities). Gizmo was a biter (although not to the point of breaking skin), I would now say Gizmo is not a biter, but has the potential to revert. This is based on the fact that his previous owner taught him that if you bite you often get what you want, and did not seem to show him better ways to communicate, he would then get extremely frustrated if he didn't get his own way and become aggressive, so given the right environment he could easily slip back into that thought pattern. Pebbles was afraid of everything and everyone, now she will go to anyone as long as it suits her

. I am not sure if she was poorly treated or poorly socialised, but it took a very long time to earn her trust, and then for a long time she only trusted me, so again I think she could easily slip back if she was put into an environment where she felt scared.
Their personality means it isn't a one size fits all for training and communicating with your eclectus parrots (or at least that is not how it is with Gizmo and Pebbles). They definitely have different motivators, triggers and ways of communicating how they are feeling, so again this may be a pro or a con.
I am coming around to also realising that eclectus parrots may not be the 'hands off' birds often discussed. My two were very much against fingers touching them, but after a fair amount of working with them (mainly touching them while they eat a treat), I am starting to get real results. Pebbles I can now practically do anything including holding her upside down in my hands, although she isn't a big fan of that (I am teaching her this, in case I need to hold her for a vet visit), and Gizmo even now seems to enjoy his beak being stroked or an occasional rub of the head when it suits him (these might not sound like much, but originally Gizmo would bite any finger that even looked like it might be coming near him, and Pebbles would absolutely freak out if you put your hands over the top of her).
[FONT="]So I guess what I am saying is if your committed and willing to work through any issues that develop then they are a great choice, but if your not, they can be a very bad choice.[/FONT]