I've used the Chicago steak, Kick'n chicken, gourmet burger, and veggie seasoning varieties and have been happy with them. The steak seasoning is pretty mild and is a nice change of pace on pork chops and steak. The kick'n chicken has some "kick" to it but is fairly mild compared to other mixes I have made or used.
My favorite is the veggie mix and I use it quite often. It has been just right on every variety of grilled vegitable I have cooked up. I typically toss the veggies in olive oil first before adding in the seasoning.
The burger seasoning is just so so in my opinion, a little too tame for me overall.