On the surface, Photos appears a natural move if you're using Aperture in a managed mode and don't need extensive editing or metadata capability. If you're heavy into metadata, Photos is poor. If you run multiple libraries, Photos can only use iCloud with one of them (your primary). It's in your Mac, import some images into it and see how you like it. There are other gotchas in Photos that can turn the simplest of endeavors into work arounds. So wring it out well before you move your Aperture library into it.
If NO for Photos: Do you want to "catalog" or browse images in Finder folders?
If the former, Lightroom even if you don't use half its functionality. The DAM side is superb. For me, it's absolutely stable (something I could never say for Aperture which I used since v2). Lightroom will import your Aperture library flawlessly. However, understand its import options and make sure you select the ones that are right for you. In my case I choose to export tifs of high rated Aperture versions to the same folders that contained my raws. If you let Lightroom do this you end up with a ton of jpegs, all in one disorganized unique folder and all with unique names. Remember once you're out of Aperture your edits will not survive unless they've already been exported to tif or JPEG.
If the latter, take a look at Lyn. It's cheap, it's simple, it works. If nothing more, it serves as a reference baseline of what to look for. There's actually not much out there. OnOne RAW was mentioned above. I'd let others shake it out first. My experience with their products suggests it will have more than a few bugs to work out at launch time, and probably well beyond launch time.
Before you begin any transition, clean up Aperture first. You don't want to do this in an app you're not familiar with. Run all maintenance routines, run relocate files if you want/need to move from managed to referenced, make sure metadata is how you want it. I also trashed 15,000 images (of 52,000) before a move to Lightroom and have trashed at least another 5,000 since. My current philosophy is if it doesn't get printed or published it gets trashed. The other philosophy is disk space is cheap.
If you really want to charge friends and family for images, any number of photo sharing sites offer shopping cart capability. Often with an up-charge. JAlbum is a cheap and easy way to do it. JAlbum was my replacement for iCloud.