I am off Tsunamis for now. I have several, all of them installed as an after-market product, and I truly have enjoyed them. However, I find their drives clunky, they don't support CV2 adjustment, and their neutral sounds are now run-of-the-mill and they all sound the same across the variants in my steamer stable. I also have been unable to get rid of that fake rod clank. Hate it!
So, I have taken, rather gratefully, to the newer QSI Titan. I would put in on par with the ESU Loksound for sounds. I haven't had to tinker yet with their fine motor control, so I can't say that's on par with the exceptional Loksound (#1 as far as I am concerned), but the two I have do a good job of getting their host locos underway smoothly at a crawl.
In respectful disagreement with Michael, I would hesitate to recommend a 'heavy' steam decoder variant from Tsunami in a small loco like a 2-8-0. There were some huge Consolidations out there, such as on the IC, but they were still smaller than the larger Heavy Mikes, the Mountains, Berks, Northerns, and the mega-articulated monsters into which a heavy variant Tsunami would, IMO, more properly be placed. A medium steam would do nicely. If you don't mind the eight year old sounds of the Tsunami, they mostly being a 'close' fit at best since their numbers are few in the decoder, and if you don't mind tinkering with the CV's controlling the motor, they running between #208 and 212, or something like that, they are just fine.