And for that matter there are so many reverbs that would work well on master. They don’t have to be ultra complex algorithms.
So focus on connectivity, interface, and budget.
Plenty of good and cheap rackmounts as well. Lexicon racks… TC M-One XL sounds great for $150-$200. Many of these racks have spdif, so you can setup a system where you record the dry from your gear over analog jacks into your interface, and the wet from the reverb over digital.
Good if you have a fear of commitment and don’t want to sacrifice another pair of analog inputs on your interface.
I had store credit at a store that didn’t stock the Mercury 7 This made the difference rather big.