I have a 4" reverb. On the scale with the current 1507 it's 251g with a 850 4s. The motors are not durable enough and I want either rcinpower 1507 or emax 1606. 25amp 4 in 1. $18.99 vs $12.99, I can get 5 emax for less than 4 rc.

i guess there isnt alot difference in quality.
the emax 1606 would have a specific 4inch prop made specialy for this motor, not sure if that count anything :-)

the most usable kv option might be more important than the size. above 3500kv doesnt make sense to me, under 3000 will be "slow". (on 4s)
i dont know their kv options, but kv would do the desicion for me if i would choose.

So my options are 1507 xing 3600, and 1507 rcinpower 1507 3800. The main difference is the rcinpower seem to have 3mm shaft. Both bells look strong. The issue I had was with bell bending. I went with the xing. Waiting on shipping times ?

3600kv should be a good choice.