Hotels matter to me and so I'm hesitant to book a tour that won't list the hotels. I realize that the hotels can change from the listed option - but I haven't had that happen too often.
I've used Road Scholar quite a few times - their hotels are pretty good but I've had some that I didn't love. I actually moved once - on their southern Italy tour - only time I've ever done it.
I did Odysseys Unlimited once and the hotels were all nice. This was Romania and Bulgaria - so sometimes they were "best available" and that always worked out except I thought the Plovdiv hotel was merely ok.
Gate One used to have a few "Deluxe" trips and I did one of those - Israel and Jordan - and the hotels were spectacular - the Intercontinental in Tel Aviv and the Waldorf Astoria in Jerusalem. I am not sure they offer that tour level anymore but it was a great value for the comfort level.
OAT is a great company, with small groups and fun itineraries. I've only traveled with them once - the Baltics last year. I had looked at each hotel to make sure they seemed ok - because sometimes the OAT hotel list is not a match for my travel style. But the Baltics tour hotels were great - each and every one!
I use Road Scholar more than any other company - I like their tour pacing and their itinerary stops - so I will forgive some of the hotels - but I do research each hotel before I book. And I have skipped itineraries when the hotels seemed off to me.
I have tried one Rick Steves tour...Scotland. The hotels were just a bit less than I like and I generally choose a slower-paced tour than Rick Steves tours - I like to stay 3 nights in most places on a tour.