i forgot the VFC 417 and g28. Have some quirks but can be made into half decent DMR's. I think the new Umarex ones are made by KWA so steer well clear of those.
Best gbbr for DMR I've found is the mws, but if it has to be 308 the Scar H is a good all rounder. They want to be DMR's that badly the auto sear selector bar breaks in them that they end up semi only anyway lol. I remove mine from new. Like all WE guns, the barrel/ bucking is appalling, so account for £50ish for a bucking and barrel. Besides that, it should be as reliable as most GBBR's. Just remember it either needs to be all steel in side or no steel inside. Swap one part out and it starts eating into the others.