I'd say it would depend on what features your looking for: 10" screen vs 8", HDMI out, Dedicated USB port, Wacom Digitizer, 1080 screen resolution.
That's really the main differences on the tablets right now as most the cheaper ones feature almost the exact same atom processor and 2 GB ram.
My Opinion: (These exclude the more expensive Core based tablets)
Best for Price - Dell Venue 8 Pro
Best for Productivity - Asus Transformer Book and Keyboard Dock
Lenovo Thinkpad 8 - Gives you a 1080 screen and a HDMI port
Asus VivoTab Note 8 - Wacom Digitizer