On a recent trip to London, I had the chance to check out the Club Aspire lounge at LHR Terminal 3. This lounge is relatively new and accessible via Priority Pass (in Terminal 3, you can also visit the No1 lounge using Priority Pass).
The lounge isn’t huge, but it’s got a variety of seating options. There are communal tables to work, smaller tables if you just want to sit with a traveling companion, and recliners if you want some rest.
The food selection in this lounge isn’t extensive, but the food that was there seemed to be of decent quality as far as lounge food goes.
All in all, I would probably choose the No1 Lounge above the Club Aspire lounge if you’re just looking for a Priority Pass accessible lounge (but I’d say that Cathay Pacific lounge is still my favorite lounge in Terminal 3 that I’ve visited so far).