We'll be in Ponce in August (that's where we know the most people, so we'll rent there for a year or two while learning the ropes from some coffee-grower friends and looking for the right land).
Everyone here grows coffee or bananas, so make sure you're not planning to sell locally.
Water and Electric are inconsistent. Make sure wherever you live has a backup water tank that you keep filled and that your fancy electronics are on a good surge protector or better yet a UPS. It wouldn't be a bad idea to get an inexpensive generator.
Internet is available too! alphanetwireless.com is a local WISP that serves the valley and surrounding mountains. I pay $60 for a 10 down/4 up connection if I remember correctly. Uptime is about 99%. Strong mobile phone signals in the area too across at least 3 different networks my visitors have had.
Downsides? Not a lot of variety in restaurants. Most stuff is fried. Chinese food even comes with french fries. Also, berries are rare and expensive.
My email is in my profile. Send me a message if you have any questions.
No, local sales are not at all profitable. The wholesale price of coffee is fixed to benefit the big roasters - our plan is to roast it ourselves and sell retail online as a boutique brand serving the mainland. Our friends already do this, and do OK with it.
The electricity is fine in Ponce (water can be a temporary issue there, too, but every house has a tank); when we do come to Adjuntas, we'll be building a solar house, ideally somewhere with its own spring water.
No hurry. It's PR. :-)