Tired of waiting for the SIPP. Jumping to Invest Engine

As it says, I'm tired of waiting for the SIPP, so just about to jump ship and go with Invest Engine for my S&S ISA and SIPP (transfer in from Vanguard).

I'm not bothered about interest on cash held and the TER for the funds I want to hold are exactly the same between T212 and IE.

Am I missing a trick here? Is there any reason why I shouldn't make the switch?