ZetosBesides what zfn said, if the idea to use premium is to fine-tune based on hardware and internet, I believe most people would require it the same way some use bp.tf's premium search. They subscribe for a month, get the info they need and just cancel the subscription. Unless they're a PC junkie that frequently upgrades stuff, a one-time check is all they need. Sure, there could be "future updates to those recommendations as the service learns more", but if people feel like they're missing out on something, they might cater to something else. Or just stick to whatever they can get for free.
I'm not concerned about people doing that since they're paying for a month of service, so they get a month of service. If they want to support the config and get the service for longer, then they will subscribe for longer. I don't think it's a big deal if people find themselves happy with one month or choose to only get it once in a while to update themselves when they need to.
ZetosI feel like a donation page would be more objective and not hinder whatever optimization the app can provide. Albeit I guess it'd raise less money.
It wouldn't be hindering anything the app could provide as it wouldn't be feasible to maintain this as a non-paid service.