Converting my barn, I've been using Erbauer for drill/drivers and demolition hammers. They're cheap and when I bought them had a 3yr g'tee. The first one was a combi and lasted a year, they sent me a new one but I then went for a separate 6 kg hammer to make recesses for joists in stone. My makita drill is good but takes normal bits using hammer action. Drilling granite just makes it hot and breaks the tip off the bits after about 5mm whereas the SDS plus bits go through like cheese, even the 18mm size go in quite quickly. For really big rock cracking a humble pick-axe and sledge hammer is surprisingly good if you're an accurate hitter.
Have also got a couple of makita cordless, 18v jobs, one li-ion with one battery t'other ni-cd with three batteries. The li-ion goes on longer and charges up quicker. I reckon the torque could break your wrist if you weren't careful. Brilliant bits of kit.