Rotel RSX-1055 and RMB-1075

Anyone ever use these together? Is there a benefit or is it just as well to use the receiver's internal amps? They have the same power ratings.
I have these for my 2nd combo system and I don't want to waste any more money on extra cables, if there is no benefit to use the external amp. Or, I could keep the amp, sell the recever and buy a processor. The kicker is currently I'm only using L,R and center speakers. These are B&W CDM7NT's and a CDMCNT, which also are bi-wire and bi-amp cabable.
Appreciate any thoughts or suggestions
As a general rule, a seperate amp is going to drive your speakers better and sound better than the amp that is inside a receiver. The RSX-1055 is somewaht dated both in terms of its DTS chip and DACs.

B&W speakers sound their best at power levels (from a good quality high current amp) close to or over the maximum spec for them. I believe your main speakers spec out 200 watts/channel but I may be wrong.

If you plan to keep the speakers and want to stay with Rotel, I would sell both components and move up to seperates using a RMB-1095 Rotel amp connected to their RSP-1068 or HDMI capabale RSP-1069 processor. You can buy the RSP-1068 for around $850 since the newer RSP-1069 came out. If you can spend more the RSP-1098 is their best processor and sounds better than the aforementioned.

If all this is too much money for your application, I'd sell both components and just go with a RSX-1067 Rotel receiver which should have enough power to drive the three speakers (I think they rate it at 100-110 watts/channel) and has all the latest DTS modes, chips, DACs etc. The sound won't be as 'good' as with seperates but it all depends on your budget and application. Used RSX-1067 receivers are running around $1100-1250.
I would keep exactly what you have. There are definitly huge benefits to using seperate amps. I am using the RMB 1080 2x200w attached to the RSX-1057 reciever. When I use the onboard amplifier there is an obvious difference. THe loss of power is noticable. Since you already have a 5 channel amp then sell the reciever and buy just the proccesor if you really want to upgrade. Selling your amp and reciever for a 1067 would probably be a down grade. And with short cables it shouldn't add to much to the inevitable wire mess. The only easy upgrade is to sell the reciever for the processor. Or do what I have and get a two channel 200 watt amp and couple it with the 1055 (1057 in my case and is probably not big of a difference). If you are looking to make some long term investments into upgrading without buying a whole new system then consider a good power conditioner (AC line filter) surge protector. I hear transparent make really good ones. I use a panamax ($300) and was ammazed at the difference. Same thing with cords. If you don't have good speaker cables or source to reciever cables then consider those. They actually made a difference for me. Couldn't do a blind test though.