Ok, I'm going to compare them in some categories: Movepool, Offensive typing, Defensive typing, Attacking Stats, Defensive Stats, Ability and speed.
Which ever 'mon gets the better comparison score will earn a point.
Movepool
First, lets see their offensive movepools. Togekiss has a decent offensive movepool, with good special coverage. Staraptor, on the other hand, gets close combat, gets brave bird, gets take down, and while it does have a coverage problem other than close combat, I think I would have to give the edge to togekiss. It has decent coverage.
Offensive typing
Both of them have the same type, so I'm going to give them both a point lol.
Defensive typing
Same thing here lol
Attacking Stats
Staraptor has an excellent 120 attack, and Togekiss has 120 Special Attacj. Both get points -_-
Defensive Stats
Togekiss has an 85/95/115 spread, making it quite bulky. Staraptor has the same hp, but the defenses are noticeably lower.
Ability
Staraptor gets Intimidate, one of the best abilities in the game, which weakens physical attacks, thus making it more bulky on the physical side. Togekiss gets Hustle, which is quite useless on it, and Serene Grace, which is quite good, however, I still believe that Intimidate is better.
Speed
Staraptor has a decent 100 base speed, while Togekiss has 80.
Ok, so with all of this, Staraptor gets 5, and Togekiss 5.
I would suggest staraptor because it's faster and it has intimidate, but your choice.
Hope this helps :)