I'm going to open this up by saying: No, It's not a good move.
Now everyone is probably thinking: What the heck Kingdra? 140 Base Power! STAB! Even Pidgeot can learn it! -_-. No one even uses Pidgeot as far as I'm concerned.
Sky Attack may have great power, and with STAB even more power, but has eveyrone forgotten that it's a two turn attack? Someone can easily switch into an Electric or another Flying type to absorb the hit. Plus, it's accuracy isn't very good. You may think 80 is a good base accuracy, but don't forget it's nearly in the Blizzard/Thunder/Focus Blast -70 section. Now I'm probably going to get a comment back saying something like: Sky Attack is the best flying move! On power it is, but no, no no no. For Example, Air Slash may only have 75 base power, but it can deliver great hits, and flinches. I just think Sky Attack isn't worth anyone's time. Sorry.