I prefer the batwing hands down over the fixed fairing. Just look at the open wind tunnel where the forks come up through the fairing. Having ridden several road glides I found the difference to be huge. I was on the fence too until I did several test rides. Batwing for me and I do a lot of 500 miles+ trips.

 

Just did a comparison this past week. I was on the fence SG vs. RG. At highway speeds, the buffeting on the RG is much less than the SG. Plus, the handling, without the weight of the batwing, feels much better. My wife and I will be using the bike for longer trips. Wanted to make sure she was going to be comfortable on the back. The RG won, in the end.
To the OP's question, I haven't really noticed much air coming from below but, I'm fairly new to the bike too.

 

Only someone who doesn't ride a shark would ask that. LOL!

 

+1 ....

 

Youse guys are funny!

Actually, I've been doing some digging among long term HD racers whose opinions I respect. I have an FXDC because I like to ride, if you get my drift. Both riders I talked to said, without question, get the Road Glide.

 

I don't have a Road Glide. That said, i wouldn't be opposed to getting one except that my 2013 is dialed in pretty good with fork deflectors the tripple tree deflector and a Klock Werks windshield and also my lowers and adjustable fairing deflectors that come on the FLHTK. When i was at the stealers one day talking to a shark rider he asked a question "how many used road glides do you see on the dealer floor?" . he made a good point. i didn't see one. just saying that the shark riders seem to hold on to them a lot longer than us batwing riders.

 

Just picked up an 2011 RGU with the adjustable deflectors. I dont get to much face wind when closed but I notice my ponytail (about 12 in) starts slapping me around at about 50 mph so my guess is the closed deflectors cause some updraft from behind. The Glide is great either way & love the fixed fairing. Especially passing semis and rounding fast corners. Reduces alot of wind shear.

 

Having had 2 of each (RG and batwings), I can tell you that with the proper windshield, the RG is a winner. Not even close. The wind coming from underneath the batwings causes a lot of turbulence. It comes straight up the sides of the tank, and lowers and deflectors don't help a whole lot. I got rid of my '12 SG for that reason. Had an '08 Ultra before that, same wind issue, even with the lowers. Had side deflectors on both of them., not a whole lot of difference.

I found the ideal windshield for me for the '15 RG, a Freedom Shield 13" recurve. Puts the air a couple of inches above my head, no turbulence with the 3 vents opened on the RG fairing. Lots of smooth wind, no turbulence.