I bought the DP Comfort seat for my M1100 EVO over a year ago and I have gone back and forth between it and the stock seat but have pretty much settled on the comfort seat. It is a lot better on longer rides and commuting but not quite as good in the canyons. Trouble is it takes about 30-40 minutes to get to the really good canyons (Palomar Mountain) so I end up spending a lot of time on whatever seat I choose.
The DP seat has about an extra inch of padding so you sit up a little higher on the bike and it isn't quite as slippery as the stock seat but I've gotten used to it.
I see no reason to spend the extra money on the Sargent seat. I paid just under $200 for the DP seat so it's tough to beat for the money IMO.