My wife and I stayed at Finca Ometepe for 8 days in December and January.
It's a genuinely beautiful location. The management and staff (and dogs) at the farm are friendly and helpful. The kitchen is well-equipped and everything worked. The beds are comfortable and the furniture, linens and towels are all in good shape. It's very clean. The AC in the master bedroom works well and keeps that room nice and cool in the evenings. Internet access is stable, and honestly faster than I expected - we even made a few video calls from the farm and the lag wasn't bad at all. The view from the large balcony is wonderful, and we spent most of our time out there admiring the scenery, wildlife, and the farm.
I communicated with the property manager Josh mostly via Whatsapp, and he responded very quickly anytime we had a question or problem - and there weren't many problems. Josh is also a good resource for restaurant suggestions and cool things to see and do on the island.
Keep in mind that Finca Ometepe is a working farm - I think they cover that pretty well in the description. If you're looking for complete solitude and privacy, this isn't the place. The staff is always working on something during the day, managing the animals or tending to all the plants. They are unobtrusive and they respect your privacy so it won't bother you, and honestly it's very cool to watch, ask questions, and learn what they're doing.
It's a good location to use as a base for exploring the island - easy to get to and easy to find, even at night. There are lots of signs to help you find the place. I especially appreciated that the staff made the letters on the sign at the entrance reflective, so they show up well in your headlights. That's the kind of little detail that helps a lot.
I was also impressed by the solar power system. The farm is 'on the grid' in the sense that they are hooked up to power from island's utility company, but that goes out pretty frequently for an hour or two. The solar power system is so good that I usually didn't notice at all when the utility power went out. The only thing that changes is that you won't have hot water in the shower until it comes back on, because the in-line hot water heater draws more juice than the solar system can provide.
We'll definitely be going back to Ometepe, and Finca Ometepe is where we'll stay when we do.