Electric is a no-brainer...
There'll be complete installation instructions, including wiring instructions--with it. If you're a bit shaky about your wiring skills, have that part done by a competent yard. As for plumbing, your current plumbing shouldn't be a mess of "spaghetti"...the plumbing to an electric toilet shouldn't be either. A flush water intake hose and a head discharge hose to the tank or treatment device are the only two hoses needed for either type. Any vented loops should remain...however, any vented loop in the head intake should be replaced with an electric solenoid valve that's wired to the flush button.As for which toilet...the best "bang for the buck" is the Raritan SeaEra.