Your preference for control mechanisms might have some impact on your decision. LionChief sets cannot be operated by transformer, only via the included remote or by the free app on your smart device. If you can get a set with a Lionchief + loco that will also operate in conventional (transformer controlled) as well as LionChief command function.
The current MTH PS3 locos will operate with a conventional transformer or with a free smart device app in DCS command mode using the included Explorer. There is no remote included in the MTH set if you prefer a physical remote, nor is a remote available for command operation unless you buy the entire TIU/remote bundle separately (about $300-350 at most dealers).
The LionChief locos will not operate via your TMCC or Legacy remote unless it is LionChief + 2.0 (not yet available I believe), but the set includes a dedicated remote, as mentioned above. MTH PS3 locos will operate via your DCS system if you have or buy one (see above).
