The SMPH vs speed-steps is a major factor why I prefer DCS when operating show layouts with multiple trains chasing each other on the same main line. The SMPH for each engine was dialed in almost perfectly (within .5 SMPH), so it never matter what you ran, pick your speed and go. everything followed each other and the occasional adjustment had to be made to slow one down or speed one up by a 1 SMPH for a few minutes.
Doing this with Legacy is nearly impossible and doing it with the CAB1 or CAB1L is suicidal. I could never get the speed steps to line up with each other as perfectly, I was always making adjustments and the operation required 110% of my attention. As a popular forum member told me, I was "busier than one armed paper hanger!" With DCS, I pick my speed with the "ALL ENGINES" mode, sit back, relax and check on it every 20 minutes. Running 4 or 5 consists on the same main line within a few feet of each other is easy.
The other big difference & issue I had with TMCC was how the system behaves when communication was lost with the base. My TMCC engines stopped and set me up for an epic crash. DCS will continue to run even if the TIU was switched off.
This being said, I enjoy using both systems regularly and would still recommend having both on your layout to maximize your fun with o gauge. And don't be afraid to add some LC 2.0 either, now that it has TMCC built in you can run some nice LC 2.0 engines with your Legacy/TMCC/DCS remotes and apps!
