Personally have used both Kenwood and Kicker amps and thought they were both good. Looking at the other specs, they seem pretty similar as far as THD and S/N ratio. The Kicker is 1ohm stable on the sub channel, but if you are running a single sub, that shouldn't matter. My guess is that the Kenwood looks like an older model and the Kicker looks newer, which might explain part of the price difference. Between the two, personally I would go with the Kenwood considering the price difference and the fact that it is actually a little smaller. Crutchfield reviews are good for it as well.
I don’t know the answer to your question, OP. Here are some thoughts that come to mind:
-The Kicker will deliver quite a bit more power as you bridge channels or reduce load compared to the Kenwood. You could view this as a less-well-controlled amp than the Kenwood, or you could view it as having more ‘headroom.’
-The Kicker will let you run the high and low pass filters concurrently, so you get a band-pass function.
-The Kenwood is a ‘cleaner’ amp with respect to S/N ratio.
There can be a remarkable difference in construction cost based on exactly what components are used in a piece of electronic gear like this. Maybe the parts Kicker uses are more durable or better at quickly delivering high dynamic power. There’s a lot of room within class D (and all of them, really) to build higher- or lower-cost equipment.
Are they both built in the same country? That would make a difference.
Again, I have no idea whether the one actually uses higher-cost components or labor. Just thoughts.
I have an older Kenwood Excelon XXV-02A 4-channel amp. I think I got this back in 2006 or 2007. I had it unused for 3 years. I have had no issues with it and it is just as great as it was when I purchased it before.
Though I may not be familiar with what everyone else is talking about in regards to specs of the amps, I can attest to the quality, reliability and resilience of the amp. I would get a Kenwood just on the price alone.
PS: I run this amp in its high pass as I run a separate amp for my sub. The amp is connected to four Boston RM6 speakers + the factory tweeters.
I think Kicker is generally just more expensive than Kenwood. If you are looking for a 5 channel amp, do a search for Soundstream Rubicon Nano 5 channel amp. I bought one for my son's car back in April. It is a very nice looking amp, and if you can find it it's only around $200. Puts out 75 watts x 4 rms @ 4 ohms + 500 watts rms @ 2 ohms. I was going to use it to power his front tweeters, front midbass, and subwoofer. Turns out it was more than I wanted to do so it's just powering his sub. I might get rid of it and get a mono amp in it's place.
Edit: it also would fit under the front seat of the Ridgeline if that was something you wanted to do. I know because I measured in case I ever wanted to use it in mine.