I own a delta elite and all I can say is..
They make bad *** markers, (for scenario or woods) Good quality markers usually 60% or more upgradable. they do serious hell raising in woodsball.
I'd say bt consentraits more on markers than accessories. But they do have a good varity of marker customizing. And a wide varity of upgrades.
But if you're a speed player, than I'd stick with an Invert mini or Planet eclipse.
Watch out...THE-EPIC-HAMSTER RETURNS!...(squeak!)