LCD is also susceptible to burn-in, albeit less so. That being said, that's why the console turns the screen off during inactivity and that's why the menu icons "wobble" - there are software-based methods of preventing burn-in and they are employed in the PSVita's OS. As for the lifespan, contemporary OLED screens can reach the life expectancy of 15 years time - it's more than ample time to play the system properly. OLED screens are just prettier than LCD ones and that's a fact you can't deny.
The bolded is highly subjective, and a conclusion I don't share.
I'd take LCD over OLED any day, given the choice right now. The latter manages to take the worst aspects of LCD and PDP--poor blacks (contrast) and relative lack of brightness--and combines them into one display tech. It was another case of Sony's lunatic, engineer-driven* business model, which now threatens to sink what's left of the company. For all intents and purposes, OLED looks like a small PDP to me, as far as image smoothness and color reproduction is concerned, minus the deep blacks, which really hurts. (And I prefer PDP to LCD, as far as image tech goes.)
(As an aside, I also seem to recall being told--by the Sony brigade--that you can't deny the PSP screen was better than DS, except that the original PSP screen was a ghosting horror that marred what was an otherwise beautiful display...as long as nothing was moving...good thing that's not important in videogames, right?
*They make some crazy stuff--their laptops are amazing bits of tech, albeit insanely, suicidally, expensive in a commodity-driven business--but they clearly have no idea at all what the broader market is interested in, across most of their product lines--a shame, really, given their history of 'getting it right'.
(And yes, I have a Vita with several dozen games.)