My son and I stayed there in 2006 and we liked it very much ($35/night priceline bid seemed like a real bargain). We loved the pool and slide, and the room service food was pretty good. Joe's Crab Shack was almost across the street, and we had a great meal there.
Be aware that the shuttle service for the Sheraton Safari does not compare to Disney transportation. DS (who was 7 at the time) had a meltdown waiting for the bus one day, which to be fair to him, was a miserable experience due to the hour long wait and the hot, hot parking lot. We had a split stay that year, with 4 days at Sheraton Safari and 4 days at Coronado Springs, and CS was far preferable since we didn't have a rental car. The AC at the Sheraton worked really, really well though, which wasn't true of CS.
(If anyone ever does a split onsite/offsite stay to save money like we did, here's a tip: Do onsite first so you can use your tickets for the offsite portion. It never occurred to me that I couldn't pick them up early, so we ended up doing a time share presentation to get cheap tickets while staying at the Sheraton. Never again!)