Well, I'm back and I can share my experiences (and some piccies) to help settle the debate.
First of all I had a fantastic time. There was 78km of piste open on the
Hintertux Glacier (it will not stay like that all summer of course) the weather was good, with cloud at the top and blazing sunshine at the bottom. I needed not to use a single drag lift during the three days I was there, only cable cars and chair lifts.
To the conditions, well you are on a glacier in spring, so you can't expect fields of fluffy powder or the piste to stay in the same condition all day. At 8.30am it is hard, groomed and bloody fast, by 3pm you can be skiing/boarding a 6km field of 3ft moguls, but hell if you can't deal with these conditions you should probably think twice about being on a glacier in the first place. I like the fact that no two runs on the same piste were the same, it challenges you and teaches you how to handle a variety of conditions. All that being said, between 9.30 and 11.30 it was absolutley fabulous!!!
Busier than I expected, late vactaion for a lot of Eastern Europeans it seemed, but still great Apres-Ski, the facilites are good enough not to be too crowded at lifts and cable cars, a little too busy on the piste in late morning, but if you are there just after 8am it looks like this......
I really was pleasantly surprised to have it so good in May, would heartily recommend it to anyone, with the proviso that if you are not confident a glacier is possibly not the best place to find it, but I've only been at this game for 18 months and I loved every minute of it...... I even got some ad-hoc rock-climbing in (came off on the flat and couldn't be arse to wak to the lift, seemed easier to climb a 25ft steep angle and board down the other side) :)
So here are some photo's and you can make up your own mind...sorry about the quality, they were taken onm my phone (was travelling light!)
The album can be seen here....
http://www.flickr.com/photos/26386569@N08/
tino