IMO, its better to train without glass and truly learn the basics. The reason, it's easier to move up to glass than to go from glass down to round dials. The RJs are 2nd generation EFIS and you will transition to them easy. However, the 737-300/400/500, MD80, 757, 767, DC-8, 727, 747-200/300, DC-10, etc. are either first generation EFIS or no glass cockpit at all. If you don't know how to fly with the old technology you will have a hard time transitioning to that equipment when you leave the RJ. DAL, UAL, NWA, AA, CO, LCC, FDX, UPS, et al fly the old technology airplanes and will for quite some time.
The military starts guys out on 40 year old airplanes with no modern technology. Why? They learn the basics. That never goes out of style.