I lease my first wave, bought my second. It depends on your financial situation. Discuss with your accountant.
Buy from Cadwell. The service they provide is second to none - fast and reliable. They can solve most issues over the phone, and if not, within warranty will provide a loaner free of charge, out of warranty for a small rental fee (<$100 for a week usually, often far less). They send the loaner/rental out before you send yours in, so there is no gap in unit availability.
I use disposable electrodes. They are cheap and easy to use. Ripping off all that tape for non-disposable is a PITA, to me, as is cleaning the non-disposables. I keep a full set of non-disposable, as they come with the unit, but rarely use them, except the ring electrodes.
I have the system set up so customized, I can do a routine single limb R/O CTS (median and ulnar motor, w/ F-waves, median, ulnar and radial sensory, plus needle exam) and have the report done in 15 min often. 20 minutes if we're being "chatty." A simple BLE exam this am took me 30 minutes.