I'm on PC and was playing solo. I'll give it a good 2 weeks of playing and then see what I think of it. It feels like everybody has a ridiculous amount of health, like my guns aren't powerful at all. It's also way more fast-paced than games I'm used to.
It feels like everyone has a ridiculous amount of health because you're not good at the game yet. There are a ton of different weapons and they're all balanced differently. You have to figure out what works and what doesn't, and what types of weapons are better suited for which maps, or even for different segments of each map.
And yes, it is very fast-paced. To me, that's the appeal. I find Halo to be entirely too slow and boring, and I hate how it takes an hour to walk anywhere. It's like being stuck playing Heavy all the time. I also find Call of Duty boring as all hell, and requiring entirely too little skill to be good.
Team Fortress 2, to me, is fun because of the depth. There are nine different classes and they all feel very different, and even different weapon loadouts for each class can entirely change how you play and what types of strategies you employ. For example, I mostly play Sniper, as it's my favorite class. I can use the regular Sniper rifle, stay at the back of the line, go for headshots, and keep my ears open for the sound of either footsteps or uncloaking spies. I can use the Huntsman (bow and arrow) and dominate tight hallways, stick close to the front line, and be constantly moving and blind-firing choakpoints. I can use the Sydney Sleeper (which coats enemies with Jarate, thus allowing teammates to do 1.5x damage to them) and play more of a support role, focusing less on kills and more on stunting enemy pushes by focusing on critical targets. And there are still like two other sniper rifles to go (although the three above are the most varied).
The same goes for every other class. They all have wildly different weapons that lead to totally different strategies if you want to be successful. You also have to learn to recognize enemy weapons by sight to counter them effectively. For example, if you turn your back on a Backburner Pyro, you die almost instantly, but you might survive if you walk backwards and keep fighting.
Most importantly, learn the maps. Stick with a couple to get started, because there are so many that you have no hope of learning them all right away. I've been playing the game for five years and there are still maps I don't know that well because I rarely play them. Figure out which styles you like best. My favorite maps are cp_dustbowl, cp_well, cp_gravelpit, cp_badlands, cp_granary, pl_goldrush, pl_badwater, and ctf_turbine. There are a few others as well that I can't think of off hand, but those are some of the better-designed maps in the game that stay consistently fun.
I'd also recommend picking a class and largely sticking with it for a while. If you try to play all of them, you'll probably fail at them all. Start with Soldier, Demoman, or Pyro, as those are (imo) the three easiest classes to pick up and play. Other classes require a lot more time and skill, or are subject to easy kills (Heavy) from more experienced players. You should also keep in mind that you're jumping into a game that most of us have been playing for five years. Everyone will be better than you, and that can be rough, especially if you're coming from a game like Call of Duty or Halo where there is autoaim and everything is pretty easy to just pick up.
Oh, and find some friends to play with. Like most games, playing it alone sucks. I almost never play TF2 unless some of my friends are online to play too.