@Zesaanzokenzoop I picked infiltrator (combat/tech) on my first run, in the original series, and was very happy with it. I chose it for two reasons: because I didn't want to play with space magic, at least in my first run, so that eliminated the classes with biotic powers; and because I like picking off enemies with a sniper rifle. There were a couple times I wished my character could use a weapon that was untrained or unavailable, but it wasn't a big deal overall. And I liked the idea of aliens having biotic powers that humans didn't, Kaidan notwithstanding.
One very convenient feature of the infiltrator class is that it comes with electronics and decryption abilities, meaning your character can unlock objects that have loot stashed inside. As long as someone in the party has sufficient skill, you'll have access to it, but with a different class of character, that would mean bringing along the same teammate all the time or else backtracking to sweep up the loot after a mission is over. I was glad not to have to do that.
In my current playthrough, which I've barely started, my character is a vanguard (biotic/combat) because that's the same as Wrex in ME1, and he was the teammate I ended up using the most in combat. And also, why not try out that space magic.
I guess the point is, figure out what abilities you do and don't want your character to have and go from there. There are plenty of websites that list each class's abilities without spoiling anything.
