Overall the best Coin Car Wash option Downtown (or at leat Downtownish...) very well maintained, well lit, everything always works.
Only drawbacks are that it accommodates fewer cars than Bathurst & Dupont and the spillover traffic from the gas Station can make it bothersome to actually get in.(doesn't affect me cause i usually go after 1AM but in the daytime it could get crowded.)
BONUS: There is small indoor booth with a "Dog Wash" tub & equipment for dog-owners!
The gas Station itself usually has a discounted prices of around 10% under the going rate, Unfortunately they have fewer terminals which contributes to the aforementioned logjams at peak times (and in the case of the gas station, even in the middle of the night.) as does the fact they lock down the store after 10PM so you can't go in to shop, meaning the attendant must waste time looking for and retrieving people's orders while everyone else waits.
The Esso on Bathrust & Dupont has been trying to match Gas price lately and has a much nicer store which you can enter, browse or use the washroom any time so it's becoming a viable alternative for Gas & variety, But if you also want a Coin Car Wash the one at Shell is the best.