I have a pellet boiler, and while it wasn't installed by them, it's one of the ones they sell, and we get our pellet deliveries from them.

Overall, I totally recommend it, with the minor caveat that I don't know what it costs (previous owners bought it). It is functionally the same as an oil boiler for the most part, but generally cheaper than oil, definitely more sustainable, and in my experience it has also been quite reliable.

The only downsides (and they're really not downsides, just things you should know going into it):

1. The ash box has to be emptied when it's full. For us in winter, it's about once a month. This is an easy task (takes maybe 3 mins) and the ash is good for gardens, etc., but it is a thing you have to remember to do. Or, if it gets full, the boiler will just shut off and give you a message about emptying the ash box.

2. The pellet hoppers they give you are gigantic, but because of how physics works, when they get low they can stop feeding the boiler (the center of the hopper over the intake pike doesn't have enough pellets), it'll have an "ignition fault". If this happens, you just have to go shove the pellets in the hopper around so that there's more of them over the intake pipe, again super easy and takes five seconds, but it IS a thing you have to do. You can also avoid this by just requesting a pellet delivery before the hopper is getting low. (If this isn't clear, just ask the MESys people to show you, they'll know what I mean and can demonstrate when they install).

3. For us, it hasn't always been easy finding people to service it – just the classic Maine thing of you call three companies, two of them never call you back. And Maine Energy Systems won't service ours (although maybe they do service ones they installed, IDK). But if they don't, TrueNorth has been great for us since we discovered them, I definitely recommend them.

Maine Energy Systems is also great to work with, we've been getting our pellets from them for years and they're always super responsive and helpful. I have nothing but good things to say about both them and True North.

In our experience so far (been in the house with the pellet boiler since 2015), if the house ever starts getting cold it's because of #1 or #2 above. So far (fingers crossed) the boiler itself has never had an issue, it only stops working (temporarily) if we've forgotten to empty the ash box or let our pellets get too low. Both problems that can be fixed in five minutes and the boiler will start right up again.

The only real issue we've had is that the top of our cloth hopper bag ripped because it was rubbing against hard edges on our basement roof. However, this was an installation mistake – a smooth board should have been installed over the bag to prevent this – and like I said, our system was NOT installed by Maine Energy Systems, so I don't think you have to worry about that. But if you're getting a cloth hopper do just be aware that if the bag can rub on something with an edge while it's fully inflated, over time holes can develop. (True North helped us repair ours, but it was kind of a pain because you can only do it when your pellets are super low, so it's better to just avoid the issue entirely if possible).

I tried for months earlier this year to get information from them about purchasing and getting a system installed, and never heard back from them besides the auto generated emails.