One thing to keep in mind--there is a difference in FW tank costs as well. I spend less money on my FW planted tank, but way more time goes into it. Once setup, SW tanks have the ongoing cost of salt and additivies, but planted tanks require fertilization and CO2, so the SW is only a little ahead. Lighting can run the same for either system, depending on what you want to keep, etc. The bulbs have to be replaced just as often for both. Initial setup costs are definitely higher for SW compared to setting up a small community tank, but if you have some of the rarer FW fish, it can average out about the same.
And, being bang-up top notch with a FW tank won't prepare you for a SW tank. You'll actually have to 'un-learn' some FW habits.