Power wise, 622 is quite sufficient for me, no issues with bouncing either. Both flashes have similar guide numbers. As for outdoors you may wish to consider a diffuser too, since lighting may be harsh depending on situation. I haven't tried the tumax one before
for tumax 386 look quite like fragile but seems like the functions are more packed like control fstop etc ...and with lcd compared to nissin 622 looks more well built but funtions looks quite limited just to share my view , seems like 2nd hand 430ex II resale prices is too high if not i would consider that too