the Radial J48 is a great di as well.
I am actually not a huge fan of the U5 (it is a very good preamp/di but a tad bit overpriced imo--you could get a nice tube di for that price--i.e. Aguilar DB900, Demeter VTDB-1, or my personal favorite A Designs REDDI, but tube direct boxes are a whole other entity than the U5) but I have preferred a few direct boxes more comparable to the U5 (the Radial JDI, J48, and JDV, the BSS Audio AR116 and BSS AR133, and the Raven Labs APD-1). Due to size issues (for live usage), I would recommend the Radial JDI or J48 and the BSS stuff.
For recording I prefer tube direct boxes over all of these, but there is something to be said for having a high quality di that fits in your gig bag.