Revchopp
The short answer is that you will be happy with either. Both have adequate support, although RCBS takes the lead here. Both are more than adequate for anything the average reloader will do. Both accept standard dies and shell holders. The RCBS can be made into a progressive with an expensive addition, Lyman has no equivelant add-on.
To be perfectly honest, with the limited differences, I'd consider which color matched my reloading room if that will help keep peace in the house!
Wayne the Shrink