I have the ONA Brixton, and I use it for both work trips carrying the XP2 with up to 4 lenses (mostly only the 14/2.8 23/1.4 (attached) and sometimes the 56/1.2 though).
It is a really good bag and my SP3 with keyboard and charger also goes in there with spare batteries, headphones and assorted gubbins. It's more or less the perfect size for me, although I think I could make the price street work too. However, no matter how gorgeous the leather looks (and it is!) I wish I'd bought the waxed canvas version as the leather is HEAVY!
If I'm not travelling I'll tend to just sling the body with the 23/1.4 or else I'll grab my ONA Roma that I've had some D rings stitched to the outside of - which gets pretty much the same stuff in it.
If I'm using my big zoom 50-140/2.8 with the T/C I'll use my Timbuk2 medium messenger bag with the small camera insert thrown in (sadly no longer available) where my long lens kit (XP2 grip, 50-140, T/C, tripod collar, assorted attachment plates, more batteries...) live permanently.