While I can't speak to the OXO V-blade slicer, I did buy the OXO mandolin...seriously, do not waste your money on that piece of crap. Both the built-in straight blade (which is not removable) and the separate waffle blade are hopelessly dull - I pressed down on the straight blade with my thumb using a decent amount of force, and all that happened was my thumb had an indentation on it (doing the same thing with any of my knives would have resulted in a trip to the ER for some stitches).
I tried cutting an eggplant, a zucchini, and a sweet potato (all raw), and ended up with ripped, mangled veggie chunks. The included guard/veggie holder is also poorly designed - I ended up with a lot of wasted veggies that were stuck in the holder but not sticking out far enough for the blade to slice them.
If there was some way to at least remove & sharpen the straight blade, this thing might have been salvageable, because it looks cool and has a nifty adjuster knob mechanism to vary the slice thickness. But instead, it was packed up & thrown in storage...in hindsight, I probably should have taken it to the Salvation Army with the last load of old clothes.
If I do pull the trigger on another slicer, I'll check out this Benriner that a few folks here have mentioned, or else I'll stick to V-slicers...the design makes me think they might be more forgiving of less-than-razor-sharp blades (because of the added slicing motion of the veggie moving along the "V").