TL;DR: If it's providing value at a reasonable cost, don't be that guy who asks "Well, if I buy the drive myself can you install it cheaper?"
TL:
This reminds me of when I was doing software development for printing systems. The system I was working on was targeted at healthcare (hospitals and large networks) and basically received data via either print job capture and data extraction or via HL7. We took that, applied some rules to determine where it was supposed to go, extracted the relevant fields and stuffed it through a moderately expensive commercial package (Jetform Central probably $8-12k, would now be open source and some SVG forms). I think installations ran $50-80k, but there wasn't anything there that any competent IT department with time couldn't develop for less.
What changed my thinking on it was the realization that
they didn't have the time or resources to develop it in-house. Sure it was nothing really special, but even at the pricing we sold at it was providing in some cases astonishing value. I'm pretty sure we fudged the numbers for the ROI in fact, because (at least to my mind) it's a lot more palatable to go to a hospital network and say "This will cost you $50k and will pay for itself in less than a year" than to go to them and say "This will cost you $50k and will pay for itself in 6 months because yes we're going to be saving you almost $10k/month that your team doesn't have time to deal with."
Take a look at what
@YeOldeStonecat has said about backups - unless they're charging at least $25/month for it, it's not worth it for them to sell. If Busybench provides the capabilities you need at a reasonable price and with reasonable polish and reliability, the cost shouldn't be that much of an issue. BusyBench isn't really a PSA - I'm positive that there's a ton of stuff in something like Connectwise or MSP Manager that's simply not there in BusyBench (notably integration with RMMs), but I suspect it also doesn't come with a lot of the huge setup overhead that I keep hearing about with those systems. They're likely competing more with things like the lower-end FreshService plans (which start at $19/user/month paid annually).
I'm overly frugal sometimes (just ask my wife) because I'm broke AF at the moment, but on business software where the highest pricing is currently at $60/month total that seems silly. I want to be paying my vendors enough that they stay in business and keep being my vendors until
I decide to move to something else, I don't want them to go away because they just couldn't make enough to buy frozen vegetables to add to the ramen.
Edit: not actually a BusyBench customer except that I signed up for an account earlier this afternoon, and may not be a paying customer for some time as I'm probably going to be doing my own billing through my grandfathered $15/mo Freshbooks account at least at first.
Edit2: Sorry if this is long-winded or cranky, I'm clearly tired and avoiding doing things that I need to get done.