I really liked it. At the beginning I didn't know whether to like or pity Pnin, but as I kept reading I grew fond of his clumsiness and all those comical and pathetic situations he faces. Nabokov's art of portrait keeps amazing me. Not only Pnin, but also minor characters are beautifully drawn.
I wish the Romanian edition had some sort of preface where the circumstances of writing Pnin were explained. Because it seems (thank God for Google) that Nabokov wrote Pnin while he was struggling to finish Lolita. David Lodge wrote a preface for this edition (Everyman's Library) where he gives a lot of biographical details, names, dates and places. I was / still am curious about all those similarities between Pnin and Nabokov himself.