I played against a Stelek style eldar army (I played Janthkin he was buffing up for Adepticon 07) with my eldar army; eldrad, autarch on jetbike, 20 harlequins, 2 jetbike units, 2 dire avenger units on foot, 2 wraithlords, 1 fireprism. 6 fire dragons in a serpent. 3 Vypers. I think the big deal is that you don't know at first how to handle dealing with so many jetbikes, or the shining spears. Harlequins lose a lot of their advatanges against a fully mobile list like that. In the end it came down to my autarch on jetbike ripping up his autarch on a jetbike but not before both of them caused a disgusting amount of damage. The harelquins were still responsible for killing half the jetbike squads, I got one of the two harlequin units in a lucky position and with turning on & off the kisses and using hit and run, I left a lot of 1 man jetbike squads that went
3d6 off the table. The other harlequin squad was wiped out, I think turn 2? And this one by turn 5 was just 3 models left. Turns 2 through 4, I was losing big time, the sheer mobility of a lot of jetbike squads had allowed them to get places where I didn't like at all. On an objective based mission it would have been a lock. However, I squeezed out an incredible turn 5 which solidly turned a minor loss into a minor win.
Against Eldar I think the Jetbike rush is stronger because the army only has 5+ saves and t3, and they nuetralize harlequins and pretty much any of the eldar infantry on foot and with turboboosting, much of eldar low
AP weaponry is made nearly useless, but against the rest of the field its a good debate, bolter fire takes down jetbikes just as easily as harlequins.
Its has a lot more to do with the calibre of opponents you play, than which style is better.
