We stayed 2 nights in autumn 2012; it was rather an undistinguished stay.
Thrills:
The hotel was located in its own gated park, in a sleepy rural area, thus it was very quiet there. The building was from the good old times, very elegant. The room had high ceilings and was well-soundproofed due to the quality of the building. There was a wedding at the hotel but we did not hear it at all from our room. The sleep was undisturbed.
The room was nicely decorated in period furniture, the hallways and the breakfast room were beautiful. The bathroom had a huge Jacuzzi tub, although it took more hot water than the hotel supplied.
The breakfast was adequate - canned juices, eggs, breads. WiFi worked well. Parking was free, very close to the building. The location was good to see Vicenza and its great villas (Ai Nani & Rotonda); also Padua as the hotel was easy to drive in & out. There was a swimming pool that we did not use.
It was probably the quietest place in our one-month voyage - no traffic or guests or housekeeping noise, no annoying music, just tranquility and silence, interrupted only by birds chirping. That was a big positive.
Disappointments:
The room was somewhat dark and not very cosy, although it was nicely furnished. The bed was not too comfortable - one side was higher than another! There was no coffee table in the room, although it had a desk (for the computer, etc.).
Hot water runs out mid-way when filling the Jacuzzi, so you end up bathing in tepid water.
There was no help with bags, they give you a trolley to do it yourself from the car. Overall the service is practically non-existent and the personnel are nonchalant. Generally, it is not a 4-star hotel service-wise. I certainly prefer Villa Palma in Mussolente over this hotel.
I found Villa Tacchi slightly overpriced. It is an acceptable place to stay, albeit not particularly thrilling.