My mixed and short review:
TF2 is ok. But some of the unlocks ruined it. The Sniper is suppose to avoid the frontline and kill from a distance, now people just use the huntsman and stand behind corners and kill whatever pops up. The jarate is a stupid weapon thougt up by childeren who think tossing jars of urine is funny. The demonman bugs me the most. The demoman is suppose to use explosives to do damage, his bread and butter weapon is the sticky gun launcher. With the Targe and Chrage may be useful, but it obsoletes the demoman's existance.
I hate with most of the hats; I like some of them. Most of them look stupid and destroyed that small feeling of serousness.
TF2 is fun a game, but it has its flaws. I wouldn't call it the best game out there either, but its not the worst.