I don't have a 'favorite' to stray from. I buy them all. I get a kick out of intermixing brands in the same train. I even MU'ed a diesel consist with TMCC and DCS in command mode and ran it (no video though, I'll have to address that next time I try that stunt).
I didn't get any of the Lionel scale autoracks because I was too heavily invested in the MTH ones--meaning I have over 50 of them (I lost track of how many I had). I did, however buy five of the Lionel mill gondolas, and I think I have 13 of their 86' boxcars. So far as Legacy, I don't have any of those locomotives. I don't have anything against it, just that I already have TMCC+DCS, and by the time Lionel started coming out with Legacy diesels that I might've been interested in enough to invest in a Legacy system, I had already bought their MTH equivalents covering every modern prototype+roadname my heart's ever desired (and then some).