I'll echo Wrathwilde's comments, and add that there are mass-market (read that, non-organic) fruit juices out there that do not contain sulfites. Most of these do contain some other sort of preservatives or stabilizers, but not all such prove to be significant barriers to a quality yeast.
Citric acid, for instance, is a common additive in juices, but it's never added in such significant amounts as to interfere with most mead fermentations (to do so would make the juices incredibly tart). An example is Welch's Concord Grape juice concentrate, which I use to make Flash Pyments. It ferments very easily. The white grape Niagara concentrate by Welch's has sulfites added, and some people have reported stuck ferments with it. I've steered away from it for exactly this reason (and for the fact that it has almost no flavor to me).
Which leads to the most important reason to use fresh fruit whenever you can in meads: flavor. Fresh fruit in the must will usually yield the better mead. Organic juices are a viable alternative too.
If I had to list my own order of fruit preference for quality meads (not Flash Pyments, good though they are), it would be:
1.) Fresh organic fruits
2.) Fresh non-organic fruits
3.) Frozen organic fruits
4.) Frozen non-organic fruits
5.) Dried organic fruits
6.) Dried non-organic fruits
7.) Organic juices
8.) Non-organic juices
9.) Canned (at home) fruits
10.) Canned (store-bought) fruits
11.) Organic concentrates
12.) Non-organic concentrates
13.) Extracts of various kinds (distant last)
You could probably fit freeze-dried fruits in there somewhere too, but I've never worked with them, and they're hideously expensive anyway.
-David
PS: Thanks to Oskaar for catching Frozen Fruits -- which I've used many times, but spaced on when making the list up the first time (hey, it was late). Purees I think I'd lump in with juices or with canned fruit, depending upon how they are packaged. Just my view.