Sharpening T15 is probably going to be its biggest downside to most folks. I enjoy sharpening and it takes a little longer than most other steels, with very little to nil burr formation in sharpening, IME. This may, or may not be a hinderance for your sharpening progression, if you rely on that burr formation to achieve an apex. I note that the edge will seem to burnish in sharpening if you spend too much time at any given grit, which can start to smooth out some aggression of your finished edge. It will take an aggressive edge and a rather polished edge, with bite.
Edge retention has been up there with many of the currently loved super steels, a la K390. The edge wears with little loss to overall sharpness, IME. The edge seems to hold initial "front end" sharpness extremely well and doesn't degrade into a "working edge" like the SXXV steels after minimal use. After prolonged usage, the edge does seem to gain more aggression, especially if initially taken to a more polished apex. I've found stropping to be adequate maintenance in keeping the apex quite sharp over extended use.
Toughness has been excellent, IME. I've whittled and torqued G-10; hacked, whittled and torqued maple; cut much plastics and I find the apex to be incredibly stable. I'd hesitate in dropping your edge angles too low (most won't do this anyway), but I am highly impressed by the lack of overall edge damage after quite a few punishing tests/tasks.
Corrosion resistance will be a definite consideration, especially so depending on usage in or around corrosive environments or mediums.
Overall, I really enjoy T15 as a steel and I find it quite outstanding for what it offers.
Make Knife Grinds Thin Again.