M800 shift function vs GCU for paddle shift

Has anyone had any experience with controlling a sequential gearbox via paddle shift using the M800 shift function as apposed to using a dedicated GCU like Geartronics? What are the pros and cons of either option?
Got a Holinger sequential in an Evo 9 time attack car with some paddles and DBW. I prefer not to have a dedicated GCU for complexity and an extra device to worry about but does a GCU give any performance or mechanical sympathy benefit over using the M800 shift function?
Been trying to compare both options, the only things I think the M800 can't do is engage reverse only when speed is zero, use a neutral lockout via button, deal with any dog-to-dog situations, start a throttle blip before down shift and maybe auto down shifts. Has anyone found ways to do these in the M800?
Got a Holinger sequential in an Evo 9 time attack car with some paddles and DBW. I prefer not to have a dedicated GCU for complexity and an extra device to worry about but does a GCU give any performance or mechanical sympathy benefit over using the M800 shift function?
Been trying to compare both options, the only things I think the M800 can't do is engage reverse only when speed is zero, use a neutral lockout via button, deal with any dog-to-dog situations, start a throttle blip before down shift and maybe auto down shifts. Has anyone found ways to do these in the M800?