I've just completed a three-night stay. My impressions:
Booking: This property is often available for under $100/nt (including hefty local taxes approaching 20%), but you can also grab a pointsaver redemption on this Cat 2 for 7500 pts. I chose the latter option.
Location: The property is located about two-thirds of the distance between COK and Kochi old town. However, that last third between the hotel and old town is significant if your primary goal is to see the tourist attractions: the under-construction Metro is a big factor in restricting traffic flow and keeping travel times on that stretch to about 30-40 min.
As mentioned in this thread, the hotel is relatively new. Indeed, the airport taxi dispatchers (perhaps thinking of the Courtyard near the airport) seemed confused when I asked for the "Kochi Marriott". The same was true for my taxi driver and two tuk-tuk drivers. To instantly eliminate any confusion, tell your driver you want the "Marriott at Lulu Mall". (Think I'm kidding? The Mall is #5 on Tripadvisor's top area attractions! Everybody knows where it's located.) It's a very good-looking hotel, tucked behind the Mall away from the highway - a very quiet location.
Rooms: as Gold, I was assigned an upgraded room on the 24th (of 25) floors - terrific bed, flat and lousy pillows, powerful and quiet A/C, bare floors, one-touch motorized drapes at the large windows and the glass bathroom partition. Nice Samsung TVs with a selection of English channels (althogh, not one of them in hi-def.) Every wall outlet in the room (indeed, in the lounge and other public areas as well) is the universal type - no power adapters needed for many visitors. I did not see any powered USB sockets, however.
Gold & Platinum benefits: Breakfast is not served in the lounge but instead in the ground floor restaurant, with a food selection and attentive service that you would expect to find in any FS Marriott. Naturally, the selection was more skewed toward veg dishes, but there were more than enough non-veg options to keep me happy.
The Sales Manager came by at breakfast to introduce herself and make sure my needs were being met. (I assume the visit was keyed by my Gold membership, but can't be certain.)
A flutist plays during breakfast hours four times per week - a nice touch. (Or, was he playing a recorder? I never could tell the difference.)
The lounge is located on the 21st floor. How do you find it? Easy, just turn right at the room bearing the plaque "Australian Government | Australian Travel Commission"!?!?!
The lounge is quite large: I stopped counting seats when I got to 50. But, it's not the shear number of seats; the tables are also large, allowing, for example, a couple to each read a full-size local paper while seated opposite each other. The lounge is large enough to hold an Indian wedding party, as I observed my first night. Also, there were separate areas with computer workstations, small meeting rooms, and a bathroom. The lounge covers both sides of the buidling, with lots of window-area for viewing the skyline.
Evening snacks were served 1730 - 1930. There were always four hot dishes (two veg, two non-veg) and several salads, salsas, cheeses and raw vegetables. Attentive staff (too attentive?) did great in clearing dishes and replenishing food items.
The lounge is open all day for cookies, candies, nuts, coffee and cold drinks, etc. I did not stay over a weekend, but I cannot believe it would be closed.
The lounge (indeed, the entire property) does not serve alcohol. They have applied for a permit, but I was told that such things take time.
Summary: a good and reasonably-priced choice if visiting the general area; not so great if you're just interested in the old town tourist attractions. This could change within the next two years, however, as the Metro nears completion. In fact, I was told that the first phase of the Metro (the stretch between the airport and the hotel) had a very limited trial run the week before I arrived.