When it comes to tankless pool heaters there is really no shortage of choice. Pool heaters are big business and the market is competitive - you should have no trouble finding a really excellent product that combines top technology with cost saving features.
It is important to think about the efficiency of the units, since most home pools represent a lot of water that needs to be heated to a comfort level! This can be costly to your bank balance as well as using energy needlessly.
One of the first things to think about is wether you need above ground swimming pool heaters or in ground heaters. Raised pools lose more heat to the environment and therefore generally need more powerful heaters than a pool of the same size that is buried in the ground. Besides looking at a pool heater, anyone with an above ground pool should look at putting quality insulation around it.
The second big choice is fuel source. Natural gas or propane pool heaters are a popular choice because the heat so well, but also because they can be installed outside so easily.
Others prefer electric swimming pool heaters, and luckily there are nowadays very efficient pool heat pumps to be had.
But since most pools are in areas that get plenty of sun, pool solar heating is well worth looking into. This can be the cheapest and most environmentally way to heat your pool!