Coaster brakes don't have set skid patches, so that wont be an issue, but having fewer pawls or less teeth for the pawls to engage would mean you have to move the pedal further before the hub starts turning. Really good freewheels/freehubs have more pawls with finer teeth to make engagement "almost" instant. The only way to have instant engagement is with a fixed gear with the chain too tight.
A coaster brake hub is probably as bombproof as it gets, but you'll probably be outperformed by other setups.
Seth Higbee
Hastings/Ionia
i played on a coaster brake hub for a while and found it to not be ideal. you can't really roll backwards or set your cranks like you can with a freewheel (and obviously not as well as fixed). also, depending on how many contact points/pawls there are in the hub, you might only have a few skid patches. i say put it on a grocery/around town bike. in those cases, coaster brakes are awesome.