Here's my 2 cents -
For the large bulk of beads made during the "trade bead era" I think the Venetians made more attractive beads, but not necessarily "better made" beads. Since I don't have expertise in lamp work, I can only comment on other aspects of the beads.

The Venetians, to my eye, had better glass to work with, in a wider range of colors, than the Bohemians or Dutch for that matter. A good example would be the ruby or carnelian reds that were based on gold compounds. They also finished most of the beads for the African trade by knocking off the surface gloss. The combinations of colors and subtle surface finishes make the Venetian beads unique (and somewhat easy to identify, IMHO).

That being said, a lot of the Venetian lamp work was average to sloppy - and while that adds a certain rustic or tribal look to a group of beads with the same pattern, I have often been frustrated by the sometimes large variations in decoration, shape & size, as well as defects in the manufacture, when trying to compose a nice necklace.

So who made the "best" beads? I think it's purely a matter of taste and also the specific beads one is attracted to.