I've not stayed at the Hilton but it's regarded as the best in town. And it's certainly the most expensive. However the chain hotels are not world class in Cameroon. Although its the best hotel, it won't be that great overall.
I've flown both AF and SN in biz to DLA. AF is better, but SN is just fine. In your case I'd book SN on the United website to get the 1K 11x multiplier. That's exactly what I did a year ago to DLA. Note that the flights stop at DLA in each direction.