Hi Mod CJ and new member ollie81,
Kikuya......mmmmmmmmmmm my favourite lawn to despise.
It all depends on how high it's allowed to become as it's one of those lawns that if not maintained becomes really spongey and cylinder cut mowers are not good on that sort of surface (sorry Jack)
Cylinder cut mowers require a firm base to work on or they will dig in on the sides creating a not so nicer finish.
Without a doubt couch is the very best for these types of machines.
Now as far as changing Kikuya to Couch, that's another huge issue as Kikuya is rather ruthless and has quite deep roots which need to be poisoned or physically removed. The only way to do this properly is to use a herbicide and poison it off fully so that absolutely no signs of life exist and then it needs to be dug out and new soil trucked in and fresh Couch planted. It's a lot of work but rest assured it's only for the very dedicated and disciplined to embark on.
One has to ask the question, am I really this sort of person or am I the sort that just wants a rather nice looking lawn without too much maintenance. If the latter then Kikuya is for you, if the former then couch is right up your alley.
Have a good look through the thread "New Playground for my Scottys" under the Lawn Care sub-forum and see if this is for you.
Cheers,
BB.