Hello,
I'm returning to the piano after 12 years of no playing (before that period, about 9 years of lessons and practising),
Great! Welcome back to playing the piano.

For the same budget, would you rather choose the pleyel "esprit" or the petrof 131 ?
Simple -- choose the one you like better. There is no wrong answer.
WHy are there so many petrof in schools ?
I don't think there really are that many Petrofs in schools. Yamaha, Kawai, Baldwin, even Young Chang -- yes, lots of them in schools... Petrofs, can't say I've seen them in schools (at least that's my perception in the US). BUT, if you compare Petrof to Pleyel and think there're more Petrofs than Pleyels used in schools, that would make sense -- Petrof makes more pianos than Pleyels, and have the production volume to supply institutions. I'm under the impression that Pleyel doesn't make that many pianos. Schools choose their instruments for reasons that may or may not apply to individual piano shoppers. I don't see how this should affect your decision one way or the other.
And do you think it's really worth spending more money to get the pleyel 131 ?
I'm afraid I don't deserve it, even if I can afford it.
The piano you own is reflective of your financial status, your taste, your class. It has nothing to do with your pianistic ability. I've seen people who don't play buy expensive pianos, I've seen accomplished pianists making do with used cheap pianos as that's all they can afford. As long as you can afford a piano, you deserve it. So if you like it, don't be shy to buy it.
