The Nexus E3 is built for recreational players wanting Nexus technology at an entry price, while the Proto2 targets elite players seeking a premium lightweight mid-kick stick.
Key differences:
Verdict: Pick the E3 if you're a recreational or developing player on a budget who wants to try the Nexus mid-kick feel without spending big money. The 451g weight won't matter much at lower competition levels. Pick the Proto2 if you're an advanced player who can justify the premium for that 345g weight and superior materials. The Proto2's balance and responsiveness will be noticeable for skilled players making quick plays, but recreational players won't benefit enough from the performance gains to justify tripling their stick budget.
Bauer
Nexus E3
Bauer
Proto2