When I first got back into the hobby in late 2004, I only knew open frame pullmor motors, I stuck with the early TMCC engines for that reason, now I wish I had ventured into can motors sooner, I have a closet full of in the box engines, and the ones on my layout are being converted to can motors and trucks along with ERR DC Commanders. The only ones I will never touch are my Postwar steamers, and Santa Fe and B&O F-3's from the 50's.
Having the speed control Command and DCS give are so much nicer, and as mentioned by John above, the sounds are excellent.