I own part of a 177FG, and my uncle owns a 177RG. They are great planes.
The FG is faster than a stock 172 of the same vintage, with a constant speed prop and 180 HP engine, and less drag. It's much roomier.
The 177RG only slightly slower than a 182, has a lower fuel burn rate, and has similar useful loads. My uncle has flown his RG from Indy to Haiti a few times. It's a nice, economical traveler. It is only four cylinders, and I think the TBO on the RG's Lycomming is 2000, whereas its 1500 on the 182 Continental, but someone else who knows more should chime in here. (Also, I am comparing 1970s versions. I was never in the market for anything new, so I never looked at those specs.) The 177 has a little more shoulder room (or just about the same) than the 182, but I think the 182 has a touch more head room. In short, I think you do get a little more speed and a little more payload with a 182, but you do pay extra dollars for it with the 182.
The FG is faster than a stock 172 of the same vintage, with a constant speed prop and 180 HP engine, and less drag. It's much roomier.
The 177RG only slightly slower than a 182, has a lower fuel burn rate, and has similar useful loads. My uncle has flown his RG from Indy to Haiti a few times. It's a nice, economical traveler. It is only four cylinders, and I think the TBO on the RG's Lycomming is 2000, whereas its 1500 on the 182 Continental, but someone else who knows more should chime in here. (Also, I am comparing 1970s versions. I was never in the market for anything new, so I never looked at those specs.) The 177 has a little more shoulder room (or just about the same) than the 182, but I think the 182 has a touch more head room. In short, I think you do get a little more speed and a little more payload with a 182, but you do pay extra dollars for it with the 182.