I've had Reach since friday and I'm currently at Warrant Officer, halfway to grade 1. I haven't had enough time to play the campaign, so I'll be doing that in a few days.
I currently have not bought anything (I'm saving for the EVA helmet or the one Emile has and black visor), so I look pretty default. I do pretty good. My team wins the majority of the games I play in and I'm usually in the top 3 for most kills or points or whatever.
I mainly play Team Slayer or Big Team Battle, but I do play a lot of firefight for the daily challenges. Any variant of Swat is my favorite gametype, though I love BTB Snipers (Especially on Boardwalk). My favorite level is Reflection (Or whatever that Matrix/Asian-looking place is called).
My favorite ability is Sprint, as lame as that sounds.
And my favorite weapon is the human Grenade Launcher, although my weapons of choice are the Sword/Hammer/Flag/Oddball or DMR/Sniper/Pistol.