We stayed at SOG about three years ago. It's a very nice hotel. Rooms are large and clean with private balcony or patio. Beds were comfy. Staff were pleasant, though not extremely friendly. There is virtually no Disney theming, so just be aware of that before you go.
We had our car with us at SOG, but we never used it all week. We found the buses to be just fine. However, unlike Disney buses, the SOG buses run on a set schedule. Unless it has changed in the past three years since we were there, I believe the theme park buses were every 1/2 hour and DTD bus was every hour. As long as you are aware of the schedule, it's no problem. I think the buses may have been a little more frequent at park opening/closing time. If I remember correctly, the buses began running one hour before park opening, so if you have an early ADR, you might need a taxi. We only had to stand on the bus once, and that was at park close.
Also, keep in mind that the SOG buses for MK and Epcot drop you off at the TTC, so you need to catch a monorail or ferry from there. That adds a little bit of time. We never minded it though, just considered it part of the journey.
A nice little perk for SOG is that it is located across the road from the Poly, so you can walk over there and catch the monorail. Some people find the walk a bit too much, but we did it several times during our stay. Took us about 10 minutes with little kids in tow.
Hope that helps!