Best depends on what you want from the optic. Widest FOV, Leica Magnus is hard to beat and its a nice scope all around with good glass and excellent illumination. I own one that sits on a combination gun, and I shoot the 12ga through the scope pretty often as the image is close to shooting with an aimpoint at 1x mag and the illumination on.
Steiner 6 and 8 are also nice, and of course Swarovski and Zeiss have good glass on them. I also have a V6 1-6x24 on a 9,3x62 and it has served me well, but the image has a certain type of greenish tint to it, so its not my favourite scope to look through.
Swarovski Z8i 1-8 is a rare example of 8x zoom ratio scopes where the image is nearly flawless on both ends of the zoom range and the eye box is still usable but they are expensive.
GPO scopes have good glass, and the 1,5-9 x32i has a optic fiber illumination, wich gives it a nice sharp look when on. We sell them at work, and from my experience they seem to be decent for their price point, but not the most durable in hard use or when used on heavier calibers.