I wear jammers and the full body drag suit God gave me. I swam forever in briefs, I just feel more comfortable in jammers. Always have briefs on under the jammers.
Usually a brief with drag suit over it...gives option of ditching drag suit if set gets to hard or need to do speed work...usually leave it on though.
I do exactly the same thing. A Keifer mesh drag suit over almost any brief (currently an Adidas).
I've tried jammers, but can't stand the way they fit, too big in the waist, too tight on my legs. They're mostly the same as bike shorts, which I tolerate while biking, and take off almost immediately after I get home.