It's a good, solid, reliable, revolver that happens to be reasonably priced and extremely durable.
I don't know of any reason not to carry one other than the fact that it's on the big side for a .357 revolver. If you like the gun and think you have a holster that will let you comfortably carry it then go for it!
I think that the GP-100 is an excellent first centerfire gun. Of course, I'm a bit biased since my first gun was a GP-100.