I have two grinders currently. Both 4 1/2" models.
The first is an old Makita that I've had for probably 12+ years. This thing is nice and light so it makes one handed cutting with a thin wheel rather easy. Aside from the rare occasion of the overload kicking out, this has been the perfect grinder.
The good: 3.1 lbs
The bad: Not a ton of power
The second is a new (< a year) Ridgid. The main reason I chose this grinder is because it is made by Metabo. Metabo is known for their grinders (and deservedly so). It is a really nice piece - almost overbuilt. It has a few nice features like a spindle lock and a lighted plug with a integral cord wrap.
The good: Lots of power, extra features
The bad: Too heavy for extended periods of 1 handed use. (4.9 lbs)
Here they are side by side: