I went through this with my sig-other a few weeks ago...
My 9 year old daughter wants a telescope for xmas and we got one. I kept going back and forth between:
- a very starter refractor model (that will get used 4 times and put on a shelf and cause minor frustration because it wont focus or see crap). Cost = up to $100 is garbage.
- a 'starter' reflector (Newtonian) scope, cost from $150 to 300 or so.
- a "good" telescope. One that I would use and enjoy with her and that can actually see crap.
The sad reality is that I know there are many cool things to see and experience and when we visit my parents house, the clear nights are AMAZING for seeing planets, the moon, stars and other things (satellites, the ISS...). The reality part of that equation is that realistically, stars are points of slightly-varying-white-colored-light. The moon is a grey ball and planets are round objects that are hard to see. The occasional comet, satellite, eclipse or other phenomenon would be gravy and not sustain the hobby.
But... the number of times we would collectively use it didn't justify the purchase this year. So sadly I gave in and we agreed to get a crap one and if my daughter likes it we will replace it with a good one. (But I am aware of this fact - how can she enjoy the hobby if she has a crap device and can't see **** with it).
So for our together activities we'll stick to various sports and geeky adventures like model rockets, RC planes, kites, board and card games, guitar, drums,...
What I would do ideally is go to the local hardware store and get a big 12" or larger paper tube (sono-tube?), order a large polished mirror from somewhere online and pick out some objective lens/mirror parts or whatever the hell you need to make a homebrew Newtonian / Dobsonian. Apparently for $100 or $200, you can make your own that is 100 times better than a commercial model that costs more.
So - I know nothing quantifiable about telescope selection sadly... Bigger ain't always better, objective-size or 'light-gathering-ability" isn't always the most important factor. I'll follow up on January 4th after being frustrated with the crap model we bought.