I have a very well used Explorer that i dont use much anymore.
The V3 is more fun to use and is much more capable on low conductors in the foil region, as you go up the conductive ladder thet advantage drops. On dimes and bigger coins the Explorers have always been very deep. I feel the V3 is very close to that depth and also much faster in the iron with better unmasking capabilities. It can find coins the Explorers mask out cause where there is deep coins the explorer finds there must be deep coins under the mask too where other detectors cant reach.
And very important for me, it has a very good true all metal mode wich the Explorer lacks and it has ground balance vs the Explorers preset. The Etrac i beleive has two user selectable presets, one for normal and one for difficult ground.
To dig out masking trash and get the true feel about the contamination of a site i need a good deep all metal mode and correct gb. With the V3i and the stereo mixed mode i think it will be more fun, and fun is a huge part of this hobby.
Both are good detectors, for me the v3 is way better and lots more fun.