Generally recommended: Shell and Lukoil.
Lukoil has been recently involved in scandals with one of its top dogs causing a fatal car accident and attempting to cover it up or something of that sort but the question was where to buy gas/diesel, not the luxury of making a statement.
Generally NOT recommended as of the last 2-3 years is British Petroleum. BP is struggling to rebrand itself by changing the sign to “BP Connect” but unless you are a fan of signs the general opinion out there is to stay away from British Petroleum or PB Connect or whatever they call themselves.
I was their client for many years, since they opened up. Then I started hearing complaints and saw two frustrated guys actually block the entrance to their station. The final drop was their habit of air pumps working in summer (thanks, I can use my own) and turned off in winter (when I would actually prefer to avoid all that dirt and mud). It was not a case of air pump down but a consistent policy practiced in all their filling stations. They keep on making OK coffee, tubes with cream, and sandwiches, and I do recommend these but be prepared for a long sales pitch about their coupons, discount cards, and specials.
Small stations are to be avoided unless recommended by locals. And local advice overrides general considerations.
Hope that answered the question by a big family gearing up for their suicidal mission. Consider retaining my availability (not hiring me but giving me eg. $100 bucks to be on the standby while you explore the Gold Ring on your newly bought Oka; congratulations but never say you haven’t been warned; the vehicle just isn’t designed for 1000 mile rural adventure) to rush to your rescue when your chariot falls apart. AND YOU OWE ME A DETAILED REPORT TO ENTICE OTHER
FOOLHA ADVENTURE-SEEKERS LIKE YOU TO LOOK FOR TROUB TO SEE THE REAL THING.