I have the MLD Bug bivy, but have yet to use it. I always seem to do my trips when the bugs are not present.
For my last trip, I was expecting the bugs to be very bad, which they were. Anyway, prior to the trip, I set-up my tarp and MLD Bug bivy.
I really didn't like the headroom it afforded, so I ordered a SMD Meteor Bivy. I like its half bivy, half bug bivy design, and its has more head room too.
I did stake the MLD Bug bivy down, which does lessen the amount of headroom.
I think, I'm going to order a MLD custom Serenity like Barnett did, with Cuben floor, rear and lower front strip, with a side zipper entry, instead of the standard front zip entry.