Many previous Milltek owners have sold the Milltek system and bought a BCS system, it's one of the reasons I went for a BCS system, forum search will show you lots of people doing this.
I saw the BCS system side by side with a Milltek and the BCS looks much better quality and is a little cheaper too, BCS will ship to you and you can get it fitted at any decent garage.
There are many happy milltek owners out there but BCS is growing a very good reputation very quickly
You pay your money you take your choice