In October, I'm following my husband out to London (business trip) then we plan to take a train up to Scotland. It seems more logical to start in Glasgow, spend a couple days there, then get our rental car and do the loop up to Oban, Skye, Inverness, then down to Edinburgh. Most guidebooks (even the RS book) start in Edinburgh. Am I odd or going to be disappointed (but can one be disappointed traveling in Europe??) or anything starting in Glasgow vs. Edinburgh?
I don't think it makes much of a difference where you start and end. I preferred Glasgow over Edinburgh, but your taste may differ. Even if you have to leave from one of them, it is a short train ride between them.
In Glasgow I especially recommend the Riverside Museum. An easy way to get there is with the HOHO bus.
I don't Think it makes much difference either, since both are only a short train ride from each other. You should note that you can save money by picking up and returning the rental car at the same location.
I did a trip like yours last month, where we took the train from Glasgow to Stirling, rented the car there and did the loop to Oban, Skye and Inverness, returned the car in Stirling and took the train to Edinburgh.
Glasgow for me! It's more earthier and personal. Edinburgh sometimes feels like a theme park to get the tourists in. But Glasgow has plenty for visitors, although the locals actually use them as well.
the afore mentioned Riverside museum is shipping and transport (the area was a major shipbuilding location)
Burrell collection https://www.visitscotland.com/info/see-do/the-burrell-collection-p246061
People's Palace https://www.visitscotland.com/info/see-do/peoples-palace-winter-gardens-p246651
Mural trail, including the 3 to celebrate Billy Connolly's 75th birthday (he was born near the Riverside). https://peoplemakeglasgow.com/things-to-do/visitor-itineraries/city-centre-mural-trail
Book the train to Glasgow (from London Euston station) as soon as possible, https://www.virgintrains.co.uk/best-fare-finder when this gives an answer there is a box saying Cheapest(all) - currently showing from £30 in Standard class, change it to 1st Class they are from £45. 1st class gets a bigger seat and regular doses of drinks and snacks included (at breakfast and dinner times this becomes a full meal service and it's all included in the price!!). For this journey 1st is worth considering if not too much more than Standard
You can start in either one, as they're less than an hour apart by bus, train, or car.
I prefer Glasgow as well, but obviously, you won't know which one you prefer until you see them both. They are VERY different, so both should definitely be seen. If you want my impressions of Glasgow, here's my trip report from last September: https://community.ricksteves.com/travel-forum/trip-reports/uk-trip-report-glasgow-manchester-liverpool-in-september-2016
I don't think it makes much of a difference. I did it the other way around because I love Edinburgh and wanted to spend more time there. I found returning the car to the airport at Glasgow a pain in the butt, though, the signage to the car return was either very poor or non existent and I ended up driving through a parkade. Maybe Edinburgh will be easier. The cities are very different, and I enjoyed both, but for different reasons. I had not been to Glasgow before, and I wouldn't hesitate to go back, but I still prefer Edinburgh.