This one is tricky. This is the first pool I reached out to talk to, and they have not replied to me at all. That makes it a little bit more difficult and this is going to be a bit shorter than the rest, but I would like to say a few things about my thoughts on Hpool.
There is a lot of misinformation and distrust out there about Hpool, but there are also a number of good reasons to be wary. They were the first group out of the gate with pooling software, they did not open the source or really even answer any questions about it. It required you to put your key mnemonic into said opaque software. They did not recommend you use other payout options or talk about hot / cold wallets. They don’t really answer too many questions at all, in fact.
I have spent some time in their discord and subreddit, and it is quite a nice community. A lot of Hpool farmers help each other out with issues and patiently answer questions for newcomers. Every once in awhile a developer will answer some technical questions, but did not respond to me or DMs from me. This is all a little troubling from a trust perspective, but at the same time I haven’t seen any evidence that they are doing anything nefarious. They are the only pool I know of working with a 3rd party security provider to keep things ticking along. I think they are genuine about trying to provide a desperately needed service to Chia farmers.
They have had some serious challenges, however. Like Core-Pool they have had issues of double-farming and misrepresenting farm sizes from dishonest members of their community. Because of this they have constantly been reporting more farm size than the reward payouts they receive. They have to retain an extremely high fee (its difficult to nail down exactly what it is. Their webpage has moved, and has said different things when I have checked. The most common number thrown around is 20%. There are accusations flown around about hidden fees and all sorts of improprieties, but there is no real way to know.
At the end of the day Hpool has been the most reliable way to each Chia since mainnet launched even if it comes at a steep cost. A lot of farmers I spoke to are happy with the fee structure since they are comparing it to the nothing they could earn on their own and there are no official pools yet. I have my reservations, and am still solo farming, but I don’t think there is anything wrong with Hpool – as long as people understand the possible risk from their software.