My information is anecdotal since it's from 2014 sign-up rather than 2015.
One year ago I did a very thorough search and comparison of plans available to me via ACA and those available to me through ehealthinsurance. As mentioned in an earlier post, plans from either side were ACA compliant but only the plans purchased via the ACA (or approved agents) were eligible for the subsidy. I chose to continue my "open market" plan that I had obtained previously from ehealthinsurance.
Prices (not including subsidy) were similar to what you found - some plans were higher on ehealth, some plans higher on ACA. However, I found I could obtain much more detailed explanations of the coverage - call it the prospectus for lack of a better word right now - via the ehealth site. The ACA site required me to all but register to obtain information on their site. That may have changed for the better this year.
Consequently, I was much more at ease with continuing my existing coverage. IMO there are too many uncertainties with the ACA plans and how they might be tweaked over the years. Yes, uncertainties exist in the open market too but I think there will be fewer surprises for my open market plan.
I don't go to the doctor often but I make it a point to inquire about issues related to open market insurance coverage and ACA coverage. My unscientific survey indicates open market coverage is the way to go. I think it's worth a few more dollars but that's just me.
Dreamin' of Streamin'
FIRE'd at 52 on 7/8/11