I would absolutely take an ms0006 over a mars, the Mars is a decent unit, but it's like comparing True Religion jeans to Levi's...
Budmaster are 'probably' even better but the prices are just fuking stupid.
I wouldn't pay over £160-170 bro.
Make sure it's the newer unit with the two green switches, which turn of two or four of the light clusters off/on not just the single switch unit.
These were being made in 2013 so even if it's been on all this time 24/7 you're still going to get 3+ years out of it.
Good luck bro
Edit: this is my opinion, based on four single plant grows all with GN lights.