Nothing wrong with those brands per se. Trane is the cadillac, Goodman is the ford. Amana is probably made by Goodman.
The 10 year warranty is a good thing, but will only be as good as the installing dealer.....shop for references.
Are you choosing an R 410 system?? It will cost more. An R22 system will be serviceable until 2020, although the costs of gas will get quite high. R22 is less than R410 now, but that will change.
I would get a contractor who will carefully size your system. 2Ĺ ton sounds small for 1800 sqft in FL. But if it works, it works.