Hi Splash
I have an Ark and enjoy it very much. It is a very stable platform to fish from and gives you lot of space for storing all equipment. It's also very robust and I use it for fishing, crayfishing, playing in the waves as well as a bit of white water rafting. A plus point for me is that it folds up and fits into your boot.
There are a few negatives, which you will have to take into account before purchasing. To me personally the positives outweigh the negatives by far:
The Ark is not as fast as a normal fishing kayak and you will have to put in some effort if there is wind blowing.
The floor of the Ark is always wet, so you will have to store everything you take with in a cooler box or similar. There is tiedowns provided for this purpose in the Ark.
As the Ark are made for two people, my experience is that it is easier if two people are rowing than one, although I usually paddle alone.
All in all- you must decide what you would like to do from the Ark. If you are only going to use it as a fishing platform, a ski would be more advisable, but if you are looking for more of an "allrounder", the Ark is the way to go.
Hope this helps!:kaykak
PS: Will 101 has done a lot more fishing from his Ark than I have done, so if you want more specifics on that side send him a pm.