Honestly, he has many positive qualities; war hero, supporter of campaign reform, enemy of pork-barrel legislation; but I haven't seen many people discuss these.
This man will most likely be the GOP candidate for POTUS, instead of bashing him, contact him and explain your qualms. Its easy to bash something or someone, rather than admit you don't care enough to do something about it.
While I admit, I'm generally biased (in a positive manner) towards vets, it ain't my sole detemination. There's angels and monsters in unifrom. I met plenty of both. I'm not qual'd to speak of his military record because I'm not very familar with it besides a basic knowledge of him being a POW.
Aside from that, your statements of "supporter of campaign reform" and "enemy of pork barrel legislation" are objectively incorrect. If you use Orwellian double speak, you are technically correct. A more realistic view shows the opposite. McCain-Feingold is an incumbent protection act, not a campaign reform act. Mr McCain is also a big supporter of expanding federal funding. He is merely an enemy of pork he doesn't have a share in. See Jim March's post for good starting points for further research.
My beefs with him are simple. Pro "Drug Warrior", very much into expanding federal funding, pro illegal immigration, little to no respect of civil rights and liberties, no understanding of technology or infrastructure (and no desire apparently to become familiar with them), and the Gods cursed McCain-Feingold. I'm gathering you're not familiar with the law, as you appear to be a McCain supporter. Here's a clue. When the NRA and ACLU are holding hands screaming that something is un-Constitutional, insanely unwise and very destructive... Might want to pay a bit more attention to it.
I've read (some) of his statements towards the GWOT. I disagree with many of his positions because I believe them unwise. Not so much the end goal, but moreso in the means to accomplish them. Burning down the village to save it doesn't work. Being sneaky, tactful, vicious, half way smart, and killing the right folks tends to work wonders. Even though I strongly disagree with him in many areas, he's much better than Obama or Clinton would be in this area. Oy.