Not a lot of access to peanut butter? That's really the only downside I can think of.
My mom and step-dad moved to Costa Rica in August of 2015. Their dream was always to retire in CR, but they found themselves in remote/travel positions at work and couldn't come up with a reason to wait. They have a number of friends in CR - both ex-pats and Ticos - and they truly love living there. Neither one are residents, so they have to leave and come back every three months. For my mom, that's easy, since she travels for work. My step-dad just makes a couple hour drive to Nicaragua and turns around every few months. Since my mom comes back and forth so much, she is able to bring back a lot of the American comfort items that they like, but they still do a majority of their spending in CR.
The COL for them is a lot higher than $1700 a month. Probably more than double that. But my step-dad LOVES gadgets, they have 2 cars, and they have a pretty fancy life. They also have a 7 figure net-worth and make over $400k combined, so I'm not judging them. I will say the internet and electricity numbers in that article are way off. Those two items are EXPENSIVE.
They live on 3/4 of an acre in a 2bd/2ba house. In the past year they've built a guest house on their property (with the hopes that my grandpa would come live with them). My mom has 6 chickens and a BEAUTIFUL organic garden. Before the guest house, garden, and chicken coop they bought the property for $182k (they paid cash). I would guess they've put another $40-60k into it (at least). Your COL will depend on how you want to live. If you want to live like an American it will be expensive. If you want to live like a Tico it will be cheap. I would personally find an in-between.
My mom and step-dad visited like 11 times in the years before they moved to CR and it really helped them learn the country. I'd suggest visiting a number of times, meeting with a realtor (they can show you places to buy and rent), figuring out if you want to live near the beach or in the mountains, etc.
If it turns out to be terrible, you can always leave.