As said, they work Ok'ish, if you download the right map for your 1098s and the cans that are fitted. But the PC only has a limited number of registers in the Eprom, so it's best to put it on a Dyno and have a custom map loaded for your bike.
Unless the PC is stupidly cheap, it's actualy cheaper to have someone dyno the bike and have a custom map loaded onto the bikes own ECU. For the simple reason that the bikes own ECU has 1000's of registers for fuel settings (among other things), as against the few hundred that a PC has.