both are a ton of fun
evos blow up a lot more than given credit for and rust out harder than any subaru. parts are getting disturbingly rare. mitsubishi hates evos while subaru loves the sti.
stis are more fun with different character. i find them to be more accessible.
keep them stock turbo and you'll be happy, the evo has a way better engine design = more power with less effort but still turns into a moneypit if you get a shitty tuner, retard previous owner etc.
atm stis are a better deal, i bought this 2016 for $16k with 73k miles. they arent worth dick because they blow up if you look at them funny and they made the same car from 2004-2021. on the flipside it makes the parts stupid cheap and its one of the few cars that improved over the years (this weighs 100lbs more than a gd but has better suspension/steering and more tire)