I would buy neither. IMHO the UT139C is a much better buy than the UT61B/C/D. It is arguable if you want a PC connection as the UT139C does not do this. It does have a back light, temperature, good input protection, fast continuity, and all the measurements you might want. The UT61E has a fast continuity test whereas the UT61B/C/D do not and it also is more accurate.
If you do not need a PC connection I would strongly suggest the UT139C instead over any of the UT61X series.