For me, the more angles, the better, so a multi-channel is a must.
I'd take a low quality multi-channel setup over a high quality single or dual cam any day, but get whatever fits your pocket.
I have an entire youtube channel dedicated to my own dash cam videos cause during my 200 mile daily commute, I tend to see some crazy $#!t
Here's a clip from when I got sandwiched in my beater XB
Another from when I got rear ended by some lady in a Tahoe
And another from last week when I spotted a drunk driver weaving in and out of traffic.
He was totally wasted!!
Managed to corner him and take his keys cause there was no way I was gunna let him back on the road in his condition