I transitioned to the euro technique about three years ago, building a 3 weight, 11 ft rod on a CTS blank. My catch rate improved, and I no longer ended my stints on the Tongariro with inflamed elbow tendons. However I found I got through an awful lot of weighted flies. The total weight of tungsten left in the river bed every year is interesting to calculate.
I tried a variation this year using a drop shot setup - now that lead shot is legal I assume it is legal to use a hookless weight as the bomb. I tried it first in Hawke's Bay where regulations are more open anyway. Someone can please let me know if it isn't legal.
Part of my motivation was to reduce the amount of tungsten left in the riverbed. Tungsten is a heavy metal, and while not as toxic as lead, is not without concern. For a weight, I tried two or three different versions. Firstly I tried a short copper chain I made from heavy guage wire, welding the links to make a 1gm bomb. The idea came from using chain as a sinker around rocks - it tends to run over rocks rather than locking up. I also made up bombs from 4mm and 4.5mm tungsten beads, using a short, braided thread loop. As a last resort I made up some lead shot bombs, drilling the shot with a .1mm drill and attaching a loop. I intend to make up solid copper bombs this coming year. Obviously eliminating lead entirely as an environmental input is the end goal.
I made up a batch of unweighted flies, from size 16 to 10. This set-up proved quite effective (in October I hooked 32 fish in a week's fishing, despite a 200cumec flood midweek). I found that I did lose a few bombs, but usually got my flies back. The bomb often came free when snagged, but didn't of course prevent the flies hooking up on branches. With the bottom fly on a 100mm dropper about 200mm above the bomb, I think I was closer to the fish than a heavy bomb fly, and far more natural. I often used a size 14 or even 16 on the bottom, and a size 10 higher up - the reverse of what I would do with a standard set-up. The hookless bomb was on 7lb, while the rest of the tippet was 8lb.
Anyway, the main advantages are that the flies can be small, and drift more naturally than weighted flies. The cost of my flies was reduced (no tungsten bead and smaller), and I lost fewer of them on snags. The appearance of my flies wasn't constrained by having beads (I used variations of a silk, glo thread or dubbed body with a throat hackle of hare's ear or CDC, applied with a dubbing loop).
There is very little about this obvious technique on U-Tube, although I found one senior US fisherman who uses nothing else. (Google "drop shot euro").