I'd go with the RCBS but not the powered one. Use a drill. The powered one cost about $150.00 more and is not that great. You pay out the A#$ for a low speed high torque motor that should only cost about $25.00. Its pretty much a gimmic. I just finished trimming (trimming, deburring, and chamfering) about 700 .223 cases manually using the 3 in 1 trimmer cutter ($45.00). I have trimmed over 7000 cases with the RCBS manually and although tideous and tiring, I still feel that the extra $150.00 for the powered trimmer is a waste.
You will need to go to the other forum (the one we can't mention but its the same as the FiveseveN) and look for a thread in the Dealer Classified for the shell plate adaptor for the 5.7X28 that is being sold. RCBS DOES NOT make a 5.7X28 shell plate for this trimmer. According to them they tried but failed and will NEVER attempt to do it again.
Or you can get the Hornady CamLok trimmer but you will have to modify the shell holder (#37) because it will NOT fit onto the CamLok trimmer without this modification. You have to enlarge the hole in the bottom of the shell holder to fit the shaft on the CamLok trimmer. You will need either a lathe or a drill press and use increasing larger drill bits (I used three) until you reach the proper diameter for the hole in the shell holder. Beware of this though because you will not be able to use the shell holder for anything else as the hole has to be opened to almost the size of the 5.7 case.
I use the Hornady exclusively for the for the 5.7 cases. I have ordered the shell plate adaptor for the RCBS trimmer (I have both trimmers). While the Hornady is more accurate and holds the case perpendicular to the cuttter better than the RCBS, the RCBS is faster because of the mounting process of the case into the trimmer. For accuracy, go Hornady. For speed of trimming go RCBS. Its really personal preference.
I can not speak for the other trimmers but from what I have read, most prefer one of the two above, with the RCBS being the prefered one.