How long have you been paying for updates/new versions for SerifPhotoplus and Photoshop?
For a long while, my wife had a photography business, and for most of the time she ran the business she and I both used good 'ole Photoshop 7. There were a few things she wanted with the newer versions later on, so we upgraded to the 9.99 a month for the Photoshop Creative Cloud. But then she decided she no longer wanted to actively pursue the business, and we just left her web site up, without actively trying to market it. At that point we deactivated our Creative Cloud account.
In the interim, I picked up a copy of Serif PhotoPlus X6. If you play Serif's pricing game a little bit, you can get the previous versions for cheaper than the current versions. They have all kinds of online discounts floating around as well.
At the time (this was around a year ago) I picked up PhotoPlus X6 for $50. They're now on version X8 for both PhotoPlus and DrawPlus. For DrawPlus, I picked up version X4 maybe three years ago, and only spent $30 on it---talk about a FANTASTIC investment.
PhotoPlus will do as a competent Photoshop replacement in a pinch, and has live layer effects (which for me is a huge deal). However, there's a few shortcuts it doesn't have that were just head scratching. The big one is PhotoPlus (at least version X6) doesn't have a draw or erase on a straight line action (which in Photoshop is as simple as holding down the SHIFT key while moving the mouse). It also doesn't have some of the basic pattern stamp functionality that Photoshop does (which I use all the time for doing terrain texturing). That said, there's nothing that's a real deal-breaker, and for the $50 I spent it was overall a good purchase. The interface for PhotoPlus is a near facsimile of Photoshop's as well, so the transition to the new software was minor. I've used GIMP in the past, and it's certainly powerful enough in most cases to work well, but I was just fighting the UI so badly, having to relearn shortcut keys, etc.
But when it came right down to it, I ended up just wanting actual Photoshop, so maybe 3 months ago I went out and bought a used copy of Photoshop CS2 for around $40. It's hardly "modern tech" these days, but it's more than competent.
Serif plays the "upgrade" game, trying to get people to upgrade every 18 months when they release their new versions. But really their product offerings are like Windows, or Microsoft Office, where you can easily skip 2-3 versions and not really miss anything.
When DrawPlus and PhotoPlus versions X9 come out late in 2016 / early 2017, I'll give them a serious look. DrawPlus has been absolutely fantastic, and if they'd fix the few minor niggles in PhotoPlus and make the rendering engine a bit faster, I'd have no qualms switching over entirely and never looking back at Adobe again.
Also, I'm sure the "hardcore" photographers and graphic designers might beg to differ, but for digital mapmaking the differences between Photoshop CS2 and Photoshop CS6/Creative Cloud are mostly inconsequential. Yeah, the UI is cleaner, and there's some "advanced" features and a few new layer effects tools and options in the newer versions, but overall CS2 is just as effective.