(image obtained from this site)
Eldar were my first 40K army way back in the 80s, and so I still felt an affinity for them when I started getting back into it 20 years later. That continues today as I work to find the right way to play my Eldar. In the 6th edition they have definitely become the fast, graceful but deadly army I want them to be, but each game I play is a work in progress on figuring out just how I want to play that out. And obviously the fastest unit available, able to move 48" in a single turn, is the Eldar Windrider jetbikes.
Much of the talk online about playing them is all about using them at the end of the game to make fast grabs for objectives. Okay, sure, they're good for that. They are scoring troops and they move lightning fast. But that's turn 5 or later, what about the first four-fifths of the game? Aren't they good for something more?
(image lifted from here)
Yes, they are! With the general increase in the Eldar stat line (originating, I think, in the last Dark Eldar codex in 2010, and making much better sense for a long-lived and more agile species), even Guardians and Bikers become somewhat elite. And when joined by a Warlock they take on an even more expansive role. Some of their potential uses I have found and been successful with include the following:
* Escort duty. Who else can accompany those grav-tanks as they bolt across the field? If you have one unit in a single tank and it's driving deeper into enemy territory, it's a good idea to send along an armed escort. The bikers can keep up, give the enemy someone else to shoot at, and return fire with a storm of armor-cutting shurikens. This is especially important when you have an elite unit aboard with a specific mission in mind, like fire dragons or howling banshees. You don't want to give them a taxi ride to oblivion, right? Don't send them in alone, send them with back-up!
* Drawing fire. I've found that jetbikes make some people nervous. Zooming around quickly like angry hornets draws attention from anxious enemies. And if you pair the bikers with a warlock who has Conceal (fortunately their default power, so you can always go that route), they get +2 to their Jink cover saves. So just moving with Conceal on gives them 3+ cover saves, and turbo-boosting gives them 2+ cover saves! They zap across the board and all of a sudden the badguys are shooting at them like mad, cuz these space elves just appeared out of no where and they MUST be up to no good, so let's spend all our fire trying to kill them. And yet the 2+ cover allows them to survive quite well while your opponent is ignoring your other units this turn...
* Anti-Tank. Yes, you read that right. I just this weekend realized their great anti-vehicle potential. I ran 4 bikers with a shuriken cannon and a spear-throwing warlock. A singing spear is S9 against vehicles when thrown. A shuriken cannon is S6, catapults fire a lot of twin-linked S4 shots, and all shurikens can come up as AP2, which is +1 on the vehicle damage chart. The bikes can leap over vehicles and fire into their rear armor, which is usually AV 10. Tank Hunters baby. This last game they killed some armored-up sentinels and a Leman Russ by doing just that! Then in the assault phase, they avoid retaliation by jetting another 2D6" out of the way.
* Assist Unit. Both in shooting and assaults, I wouldn't bet the game on the Biker unit. They can be deadly in shooting, true, but I'd only initiate an assault if I were desperate. Or if they were joined by an Autarch on a bike. Dodging around and shooting guys up is one thing, diving head-first into combat is another. A warlock's witchblade and special powers might help, but they aren't enough to bid a full-blown attack on unless the target is pretty soft. They could be good for assisting other units, though, like in an assault. Gaining those extra Init 5 WS 4 armor save 3+ models to help tip the scale is a good idea, but again, going it alone might not be good for them.
Well, that's my take. I feel like the Eldar players at large are generally underselling their jetbikers. In an Eldar army (just like in their fluff), your units are few and elite by nature, so you have to make the most of each one. We don't have throw-away units; or if we do, they are thrown away at high cost and their sacrifice better be worth it. All Eldar units should be considered adaptable and able to function in various new roles. We Eldar are an endangered species, after all, so we need to be able to cover a lot of bases!
(borrowed from here)
p.s. I also think each Windrider squad should be allowed to include a single Vyper for high-flying gun support. Hey, Dark Angels can do it!