Depends on how much it would be used and if it might get rained on etc. I think suede looks nice when brand new, but the nap can get worn, grease really affects the appearence and then it makes the saddle look old before its time. That said, I don't know what the fashion is in showing, so it might be worth taking the negatives and having one anyway if judges prefer them!
I have a suede seated/knee roll ideal WHP saddle and i LOVE it. Its been on my wish list for many a year and last year I took the plunge and got a new one fitted. I use it for every day riding as well as showing, schooling, hacking the lot, and it is holding up really well, I've had it over a year now.
The only thing I will say is that is seems to wear through jods quicker but then I suppose it would.
I think they look really smart and give a bit of extra grip which means a lot to me on my spooky unpredictable welsh!
Also, look around in the show rings and you will see lots of worn looking suede saddles, this will not get you 'marked down' in any way. Tack doesn't have to be new, just correct and well fitting.
My WH saddle has suede knee rolls and seat and it's really comfy. You certainly feel quite secure in it. I use it for everyday and it will be used for the show ring when the pony is ready to do ridden classes. He has recently been backed so it's nice to feel secure when we have the odd spook!