I like my Aquacomfort. It has no cooler, but i'm in the NE and dont need it.
They all pretty much work as advertised. Just realize when you see the BTU out put, that is the BTU at OPTIMAL conditions (i.e 80 degree air temp, 80% humidity, or somewhere there bouts). You should look at the curve. Most run anywhere from 80,000-120,000 BTU depending on humidity and ambient air temps.
Some brands use titanium heat exchangers. They are touted as being impervious (nearly) to chlorine/salt/etc. You will lose some efficiency. Copper heat exchangers will allow the HP to operate at cooler ambient temps. If you keep the chemistry in line, there is nothing wrong with copper, IMO. Mine has a copper exchanger. Since i live in a northern clime, i liked the heat curves better. For you in the south, titanium probably would not make much difference. The warrenty on the heat exchanger is very good for any brand i looked at.
Piston vs scroll compressors. Scrolls are a bit quieter. Maybe you might see a little better efficency. If the price difference was huge, the scroll would not be worth the extra, IMO. But again, my opinion.
Heat pumps are like anything else. The best one is what you have (if you like it and had no trouble) or its one you sell if you are a dealer
A dealer can give you the upside and downside of the different brands. Just take what they say with the proper amount of due diligence if they only deal in one brand