Honda CV Boot is an exact OEM replacement. Split boot literally is split all the way on one side allowing for install without removing any major parts. Go with OEM.
Honda and most other large manufacturers use a one piece seamless boot that requires disassembly of the cv axle in order to service. A split boot is a short cut repair that just wraps around where your old boot should be and clamps in place.
Oem boots are typically one piece. This means the suspension will have to come off on one end or the shaft has to come out of the transmission on the other so the boot can be slipped on. Two piece simply snap around the shaft and are secured in place.