To add a viewpoint to this thread as it would have been handy before my trip. Just came back from a 5 night redemption at the Marriott Tblisi and 1 night at the Tblisi Courtyard (both bargains on points at 15/10k respectively vs $250+ on cash payments) whilst on vacation.

Marriott
Good lounge with a nice selection of foods and good food timings (breakfast till 11am, evening food supposeduly from 5.30pm-7.30pm, followed by deserts till 9.30, but in fact when I was there the food was frequently out till past 8pm, in summer so the hotel was quieter) and generous portions - you could theoretically eat out of the lounge if you wished. The food was also European based, no Russian style pastas or breakfasts, which was a positive compared to an experience in Yerevan/Armenia last year. I had an executive room which was spacious but without any real views (to the front of the hotel, the main avenue of the city, so just traffic - others looked onto an internal courtyard, as did the lounge). The hotel corridors were very dark with no natural light, but the public spaces were pleasant. The lounge was key accessible 24/7 which was a nice benefit as the amount of soda/water you drink in the summer here is considerable (more lounge details in the relevant thread).

Courtyard
I liked that I was recognised as a Plat Premier explicitly by the front desk manager, who also commented I was the first he had seen visit the hotel. This resulted in an "upgrade" to one of the best rooms in the hotel (I appreciate Courtyard's don't have suites) - a slightly larger corner room with a lovely view of the main freedom square and looking onto a gold plated church on the other side of the river. The welcome gift of icecream was nice, and appreciated that it was doubled to cater for my wife also being with me. The location of this hotel is slightly better, it is right next to the metro and closer to the old town and museums, but in truth it is only 500m from the Marriott which is further down one of the main avenues. Public areas were clean and like a Courtyard, nothing special or Georgian (beyond lots of wine being sold).

Conclusion
So, if I return I'd stick with the Marriott for the lounge (which saved a lot of money and trips to find water/sodas as there aren't really nearby small shops), if I didn't have lounge access then the Courtyard would be my preference for a superior location and view. Otherwise they use the same cars (to/from the airport, mercs - for the same price 59GEL including tax at 19%), wifi provider (available in both hotels and free as a plat, both wired and wireless options), tv channels (around 60, including a good selection of English language such as Nat Geo and a few Discovery channels), size of TV and so on - the hotels are owned by the same company I believe.

As a final point: The executive level on the Marriott comes with a free (one-way) transfer to/from the airport, and since I was a Plat I was upgraded to this level - it may have been a mistake by the night staff when we arrived but we were comped our car trip to the hotel? Put me in a good mood and nobody re-added to the bill, suspect they should tighten their wording to make it clear that this benefit only applies to paid stays. "In Georgia we pay you to stay in hotel" came to mind, so we spent that 59GEL on some tasty wine!