Mainly price first. refractors are expensive. Sometimes a cheap OTA does not mean cheap extensions, fittings, and accessories.
Second is overall portability, I like small refractors for grab and go. I'm not buying a new scope only to let it sit in the box because finding out that my mount is not suitable enough.
Third is optics, mainly because when it's great at low powers sometimes you just want to swing it around to see the planets. Better correction too for photos.
Hence fourth is the aperture. With great optics, it can compensate for the power somewhat, so I'm not that concerned. Besides, it's also tied with portability.
Lastly is finding out problems and reviews. What problems it has based on other's experience, that might pop up in the long run. Add that to the price equation for any additional tweaks or accessories needed.
Edited by Bowlerhat, 19 August 2019 - 06:17 AM.