I'm using this app and it is not bad, and for iOS I recommend it if you really need to play on KGS. For blitz games - it is not good solution, but for games with no time or with longer time setting - it's good. BUT - this is linux, and linux and Java does not go well together. It means that you can play on kgs but because of Java you can experience crash or freeze of KGS ([edit] in the past it crashes about every 20 minutes, now it is more stable and I didn't experience any crashes lately).
It all depends if you have a money to spend on it and really want to play on KGS - if yes then go buy it, but if you want just to play Go there is PandaTetsuki, Tygem, WBaduk for free so I'm not sure if this is worth this 20 bucks they want.
[update]
today evening or tomorrow morning I will record a short video how it works on iPad. I will also try to wait until KGS crash to show all process and how long it takes to login. This java crash issue is already sent to developers so I think there is hope to minimize such events, but Linux and Java used there are not their piece of software so this could be hard to debug/fix.
I need to mention that I didn't find this app buggy (it is really simple)or sluggish or unresposive even that I live in Poland and servers are in USA. It is remote desktop so you can't get super speed abut it does good job in delivering full desktop experience on iPad without running your own server/computer.
And most important thing that guys above are missing - you don't need computer to run it, because it does not connect to your machine. This is why it cost $20. It is not simple remote desktop like TeamViewer, NTRConnect or Splashtop that links you your home computer. You connect to Linux based server, you have there 3-4 gigs for your docs, files etc, there are full Linux with OpenOffice. And you can you use it as you like.
So there are pros and cons. Wait for the video
