I found Henkei Alert sold out pretty quickly in online stores like HLJ, so I personally skipped it because I already had Henkei Lambor and Sunstreaker... wasn't prepared to go to extra effort or expense for a repaint. Generations Red Alert on the other hand is really easy to find (he's still peg warms in some stores), so it was a great opportunity for me.

I like Generation Red Alert's black head as it's more G1 accurate (as the toy and comic had black heads), although as a group display Henkei Alert's red head does off set pretty nicely against Sideswipe and Sunstreaker. As you said, while Henkei Alert is much nicer than Generations Red Alert, Gen. RA is okay too.