Firstly, this is our 3rd cruise and all with Thomson's so my experiences are based on this. I got interested when the Mrs mentioned the drinks packages and no infernal drinks and tips bills.
The Spirit is clearly on the older scale and to be fair she's showing her age a tad. This shows in paint jobs and fittings-but there's no issue at all with cleanliness, which is excellent. I don't think I'd like the massive ships but realise some don't like the Thomson's tiddlers.
There are plenty of bars. My fave was Raffles on Deck 5. Casual atmosphere but light and airy, there was a good atmosphere but usually a seat. It's next to the Broadway Show lounge so also good for pre-show tipple. Be warned mind, if the live music is on and you're by the speakers, you'll need to shout to be heard. The musicians are excellent, just deafening in places.
Had a touch here. Although we were 3/4, on Deck 8 there's a few 3/4 cabins due to size. It was brilliant. No neighbours (next to gym-couldn't hear it) and a silent lift about 15' away. Loads of storage space. No long corridor schlepping. Also goes straight onto the main aft deck areas from 8 down to 5. Really good.