My wife and I stayed in this hotel for 4 nights last summer. It is a beautiful property in a terrific little (and old) town about an hour or so east of Rome, in the hills. Fiuggi is the site of some famous Roman baths, and there are still two public baths in town, although we didn't try them out. There is an outstanding family-run restaurant in the old town at the top of the hill (sorry, but I can't remember the name - the concierge certainly will) but beware: there is no taxi or bus service down from town after 8pm, so you'll either have to call the hotel for a ride (which I imagine would be forthcoming) or walk back down the hill to the hotel - a brisk 30 minutes or more.
I have 2 criticisms of this property. The first is that they appear not to even want to particpate in the SPG program, and certainly didn't offer any SPG platinum recognition other than the mandatory points. The hotel was essentially empty during our stay, but the best available room wasn't offered even after a polite inquiry - yet suites of all types were bookable online. The second criticism is that the price of goods and services, including restaurant meals, seems to be completely unrelated to the printed price. Dinner in the first-class restaurant ended up costing about $40 more than the prices in the menus, and I'm not sure why. The spa charged about $20 more for a massage than the listed price, too. And we had several minor overcharges at breakfast at lunch.
The staff was friendly, and Tiziana (a lovely young lady who works in the restaurant) is a terrific resource if you're interested in learning about places to go in the surrounding area, or where to buy the local provender.
I'd go back, but I'd know enough not to expect any SPG juice, and I'd be keeping copies of every bill so I would have an audit trail at checkout. Enjoy your stay - and do try the local wine (Cesaneze del Piglio), you can find very drinkable and affordable bottles at all of the local restaurants even though it isn't a highly celebrated DOC wine.