Nope, 720i is the way to go, 725x has no "Auto stop/start", I also like the durable metal case of the 720i, rugged good looks vs "plasticky carbon finish"!!! 720i wins hands down...
Your laptop will need to have an infra red port, the software will load a generic driver for that port. Otherwise you will need to have the Polar Infra Red USB thingy mebob! Once you have either of these, line up your wrist unit with the infra red port, set unit to "connecting" and fire at will (Terrible instructions I know, but you have read the manual...)
