What can I say, guardians moving 12 -18" with a 3+ save is priceless. Toss in a Farseer and a Warlock and you have one powerful unit. Some use a seer council but I'm trying to move away from that. The fluff for my Craftworld is that its a scouting group from Ulthew, so they have limited resources and access to aspect and seers. With that said here is how usually set up my army.
I wont go with less then 8 bikes in a squad usually, the idea is with 2 being devoted to cannons you only have 6 bikes to soak up any wounds so numbers help and work. Thats the base of my two troop units, I'll toss in a warlock with enhanced or embolden depending on my point restriction and a farseer with Fortune.
Two bike units supported by a warlock and farseer in each can be really tough to beat and they can hold their own against several opponents. Some weaknesses I've found are its cost and not being able to deal with AV14. Now thats the thing with Eldar players, we usually build our armies so each unit has a specific role and each unit supports the other. I use these units for popping small rhino, mid size battle tanks (the ones with av10 on the rear), multiple objective grabbing and supporting assault units. So this is my core and I add other units to help support, units like swooping hawks, vypers, dire avengers/guardians and several others.
Well there you go, thats just my take on Eldar jet bikes, again I prefer not using a seer council because I have had more luck with this combo so far. That and my council gets targeted and wiped out early. lol