I visited the beginning of Feb 2013. There seem to be many conflicting reports on the resort and I shall try to help by giving an unbiased view. I have skied in many resorts in a number of countries in Europe and can therefore compare them to the Gastien Valley.
The Gastein valley is not typical of many Austrian resorts, I found it to be much larger than had been suggested by some posters on this site, certainly enough to keep an intermediate skier happy for a week.
I spent most of my time skiing the Angertal and Sclossalm slopes and spent 2 days in Dorfgastein, I also had a trip out to Hochkonig area for a day; this is covered on the Ski Amade pass which also covers some other major resorts in the area.
The Gastein Valley slopes are, in my opinion, at the upper end of their grading and best suit intermediates who are willing to take on some slopes that are fairly steep. Some of the blues are fairly steep or have steepish pitches and many reds are challenging, although there are a few less steep slopes I would not really recommend to a beginner as there is little to progress to that does not have some sections that may worry beginners. Experts may get bored after a few days unless they spend time off-piste.
When I visited the slopes were busy due to Austrian half-term, though the longest queue was about 20mins for both the funicular and cable car; it is now time that they were replaced with a fast modern 2 stage gondola.
Piste marking was lacking; in poor visibility it was possible to find yourself off-piste so great care was needed. Grooming was good but due to it being busy many runs became badly cut up and some had moguls due to this, a good example was the Hohe Scharte Nord which by the afternoon was almost top to bottom moguls. The steeper runs were the most badly affected on the whole.
Dorfgastein was, in my opinion, much better. Although busy, it was less so and the runs were far better, they were wider and there were more of them in the trees helping with visibility, the snow seemed better in this area too. Probably a little better for beginners too as a few less steep runs.
On-mountain restaurants are good with the standard Austrian offerings and pretty good value.
The bus services were like everything else: a little busy. They were, however, frequent and I had no problems using the service to Dorfgastein. The others seemed regular too and the round resort bus from hotels was frequent but sometimes full.
In conclusion, the resort is a good choice for those who like red runs and are happy to have a challenge. It can get pretty windy at the top and Dorfgastein is best for poor weather days. I will definitely return but think I would try to visit outside of the school holidays.