Even though the 7125 has 7 channels you don't have to use them all. Many people use the extra channels to drive another zone or to bi-amp their main speakers. The outlaw amps are different than receiver amps in that they are all discrete channels. Under the hood of the 7125 are 7 separate amps which can be used to feed anything you want. The 7125 also provides some degree of future proofing. You may only need 5 channels now, but what if you move and can support 7 channels in your new digs. Depending on the efficiency of your speakers, the 7500 is a great 5 channel amp with lots of reserve power even for those that need a lot of power. The 7700 is the same amp as the 7500 but with 7 channels. The 7200 is similar to the 7125 except for output power. In the past I have made the suggestion for one amp to combine all the capabilities into one box. 2 main channels from the 7900, 2 surround channels from the 7500 and 3 support channels from the 7125 for the center and the rears. For the record the 7125 weighs 51 lbs and the 7500 comes in at 80 lbs.