How is he as a tank? What are his weaknesses?

Any specific tips to keep in mind while playing him? Is he a good buy and viable pick?

I haven't seen him do amazing unless it's my friend Kyle playing him but Kyle is good with any champ. With AD champs being better than AP champs most of the time and factoring Galio mainly being the MR stacking version of Malphite and Rammus I'd probably rank him as a lower pick. He is pretty good at clearing minion waves though so he might be a decent bot lane pick.

He can perform well but I don't see him often. He's certainly viable and provides a lot to the team, espeically his ult, just don't get tempted to stack ALL MR ALL THE TIME ONLY MR because of his passive.

Galio is hard to kill, but he can't fill the role of a tank in the top lane. Other then his Ult, he doesn't have any reliable hard CC to protect his team mates. His W can nullify the effects of Black torch very well, but can't really save squishy teammates from focus fire. However in the bottom lane he doesn't need to protect anybody, so he's quite viable as a bot.

Galio's main weakness has always been his long cool-down and running out of mana from spell spamming, but once you get Athene's Unholy Grail his main weakness is gone.

Galio's issues is he can't do much, due to needing too much. Items wise.

1. If you want Galio to deal damage, then his damage is outdone by many, and is entirely reliant on relatively slow skillshots.
2. If you want to deal damage, you need to spend gold on damaging items, and you're not tanky at all.
3. If you build tanky, you deal no damage, and you don't have enough CC to be a real tank, you're more "I stand and try to pathing-block you from passing me", which you can do with any model really...

I like Galio, but I'd probably send him bot and try to be a pusher.

Bot laner, has some potential to switch out with a top champ if need be. Some.

Try this: Use your ult on an enemy champ when they have a good build-up of minions. The minions really, REALLY ramp up the damage dealt.

I really like Galio, but he's just not very good on Dom at all. His only teamfight presence is his very long cooldown ulti, his wave clearing ability is only so useful, and you have to choose between tanky (eg. everyone ignores you) and high damage (eg. everyone just kills you).

Unlike SR, you're never going to build up a big CS advantage on Dom, which means you're taking on bruisers and AD carries with the same gold that you do. It doesn't end well.

The only way he's a viable pick is if the enemy takes a bot laner AP who fares very poorly at top... but I don't think there's many champs who suffer more from rotating top than Galio. Maybe AP Malz (why not just AD?)? Soraka possibly?

(And trust me, blind picking Galio bot into Jax or Xin is just painful. Very, very, very painful)

I love galio on dom, but I agree he doesn't play like a traditional tank. I play him more like a beefy support and have had really good success with him. Although I haven't tried him in the new patch so it could be a bit different.

How I play him is by maxing his wind and shield first over his skillshot nuke. You're never going to be a damage dealer unless you're going agaisnt a lot of squishies so I focus more on his team abilities. This lets you protect anyone, speed up your team, push lanes, and do some damage with an easier skillshot to land. You then save your ult for when the other team tries to tower dive you I usually run garrison and heal on him to further help your team out. I agree though, ADC's will melt you very, very quickly which is very untraditional tank? Play him more like a support mage and you may have better luck.

I love Galio, but he has a very "set" build if you want to tank and deal damage. It's pretty much - Athene's, Abyssal, Frozen Heart. That'll give the damage, defense & CDR that you need.

In that Pre-S3 patch where BFT & Teemo was OP, Galio was a great pick. Bulwork on someone that hit a Teemo shroom and you got 1/4 of your HP back.

He's a tough champ to play, but rewarding. It stinks in blind pick, because you don't know if he's going to be obsolete or awesome. Sometimes I'll get lucky and they'll be triple AP or something. He's also great at point defenses. His ult + Garrison is amazing.

I choose Galio top over Maokai because he more directly supports his friends with buffs, while Maokai is more enemy-oriented with a shorter-cooldown hard CC, and only one buff. Yet I consider them to be very similar.

Galio's Level 3 damage is surprising, even his auto-attack nets me a surprising number of kills. Resolute Smite is a soft peel, and stronger when combined with Righteous Gust. Both the utility and the damage of Resolute Smite improve with levels, and enemies are not always big MR builders. To capitalize early game, I would recommend levelling Q before the enemy gets his second Null Magic Mantle. Then W, not E. Because the enemy will start doing some damage, and your pal needs the extra armor while they run from the guy you slowed.

Galio's ult synergizes well with Odyn's Veil. Catalyst is a viable alternative to Chalice, especially with the speed of experience gain on the Crystal Scar. Mercury's Treads are a good choice against any team, but on Galio it is better, so I rarely have to think about boots; if I'm doing super-well I might get Sorcerer's Shoes but rarely. For armor it is usually Frozen Heart because of the CDR and more mana; often I buy at least Glacial Shroud while sitting on Catalyst, instead of trying to finish Odyn's and having no armor for too long. Once I have Odyn's Veil for the health, I can't always buy Abyssal Sceptre. The most important thing on a support-tank is CDR, and I top it off with a Kindlegem item before fitting Abyssal or Void in. Try Hextech Sweeper.

People complain that tanks don't do damage, but CDR is a damage source. And you don't need to do damage late. You do some damage early, and lategame you need to turtle and bodyguard. Anyways, if you can't get into Galio, try Maokai.

(Edit: My real name is Vicki Nemeth.)