Yes, it is SLOOOOOOOW. Once you have that thing on gas, electric or automatic; DO NOT OPEN THE DOORS FOR A MINIMUM OF 8 HOURS. I learned this the hard way. Wife kept opening the door ever hour or so "is it cool yet?" set us back 2-3 hours each time.
Our RV is only 1 year old and we had it serviced. Since I left it at the dealership, we emptied the refer/freezer and defrosted. Took sooooo long to re cool, I became concerned and called the RV dealership. They told me highly unlikely any refer issue, just takes what seems forever when you have all your food packed and iced in coolers on a 100 degree day!
We finally went to the store, bought MORE ICE ( about the same cost as diesel fuel ) went to bed and said the heck with it. Next morning, refer ice cold and working properly.
Patience seems to be the key. Unfortunately, we have little of that.