He is a great champ to learn. He is OP if you have the dodge runes for him simply because dsp champs basically cannot hit him. A caster is required to kill just him and even then at the late game he has so much HP that a single burst from a caster can only get him down to about 1/2 HP. He has both damage and survivability going for him and is thus annoying as hell. He can and will 1v2 and 1v3 and still win.

People will not complain if you choose him, if they are on your team. The enemy team, especially after you destroy them on TT, will though lol. Make sure to get dodge yellows once you can purchase the Tier 3 runes at level 20.

He is a strong champion, but not extremely op'd like some people seem to believe. I doubt you will ever have teammates complain about you picking him.

The most important thing though is you found a champion you have fun with. As long as you are enjoying who you are playing, you shouldn't let other peoples opinions bother you.

Guh, Jax is a beast, his damage output is ridiculous for his survivability. As a result though, he is almost always cced/focused in 5v5. In 3v3 though... he can be frustrating.

Well, I feel cwatz pretty much hit the nail on the head, but I will say this: champions are always getting rebalanced, and as new champs with new mechanics are put out, the relative strength of every other champ is always changing. Characters that were once very powerful can and sometimes do get nerfed pretty hard (Twitch). Champions that have been collecting dust for months can get a huge buff and get popular as all hell (Kayle recently). Play someone you like, and don't worry too much about the future.

That said, Jax is pretty awesome at the moment, so you won't be catching any complaints for a while about your champ choice.