E.M.
My son loves the Britax Parkway Express Booster, as he can take naps with a head rest. It doesn't bother him any other time, either. However, we all still still prefer the Britax Wizard.
I personally like the Recaro car seats. They have the option of converting to a booster, but I think a 5 pt harness is the best way to go whatever you choose. Personally, I think 2 years is VERY young to be in a booster; weight limit or not.
My son is almost 4 and can easily get himself in and out of a 5 point carseat, so there is NO reason for me to want to put him in anything less safe. It is actually easier for him. I found I had problems with him unbuckeling himself a lot more with the boosters, so we took them out of the car for the time being.
Also, look into the Britax Husky/Regal. They are a 5 point harness for larger children.
Hope this helps, Liz