I am starting to sense a very serious bias towards the Land Speeder Typhoon! People seem to think that rending is king, and in *cough* SOME cases, I guess, it is rather nifty. (Kayvaan Shrike, anyone?)
Because of my unending hatred for all things cheese (it must be some foul creation of chaos) I want to point out a few alternatives, because you fine fine folk deserve more than the silly looking tommygun on the front of your flying shoes.
First off, for the basic points cost of the speeder, you have a fast skimming heavy bolter. Now, my mainstay army is the Imperial Guard; if I ever found a way of getting one heavy weapon on a 12" move/shoot vehicle was even feasible, I would pay at least what we SMurfs have to pay. From there we only have to follow the yellow brick road, oh yes, as the options these fine lil pups carry are quite varied.
First off, we can turn this deepstriking, up-to-24"-moving monster into a vehicle destroyer with the refitting of a multi-melta instead of a heavy bolter. The implications for this are obvious, and the great range on a multi-melta (remember, IG background) is a surefire distraction, especially if you intend to deepstrike a small-point-cost distraction. UNFORTUNATELY, you aren't able to combine the multi-melta and the ass.cannon (which both have the same ranges, oddly enough) but you ARE able to combine the multi-melta with a heavy flamer! What good would this weapon combination be, you might ask? Popping sardine cans, thats what for! Transport vehicles, if not destroyed from multi-melting madness, would have to evacuate all its passengers, and because you deep-striked within 12" range, your new targets are now ready to be flaaaaaamed.
For a few points cheaper, you can take the second, under-rated version of the tornado, fitted with multi-melta and heavy flamer, and be all the better at whatever it is that you do! Its not really that much more risky, as the speeders are gonna die no matter what range they get shot at, and personally if possible id rather have my enemy assault my vehicles (skimmers especially) then shoot them dead.
Next off, we have the Typhoon variant of land speeder: my favourite. While you are able to replace the bolter with a melta again here, there really is no purpose in doing so: your changing your loadouts effective range from 36"-48" to 24"-48". The range on the Typhoon is what makes it the clear choice: Harassment from afar, and for how few points your paying, a very potent anti-infantry vehicle. Grouped with the fact vehicles do not have to roll leadership to choose target, and it has a twin-linked blast template, the potential for doing harm from afar is nearly unmatched by anything else in its cost range. Keep an eye on your range, and you can even force casualties from the front (remember, cant remove normal shooting casualties from beyond the weapon range) potentially dropping off key special weapons before they become a threat.
In closing, for a fast attack that epitomises what fast and attack stand for, especially when paired together, its my belief that the tornado ass.cannon model can certainly get lucky and perform to what must be some of your guys' expectations: I've found out the hard way relying on 6's is a good way to get yourself deep-sixed. (never play an IG assault army vs the death guard) For a quick and resilient annoyance that will either earn its meager points cost in drawing fire (most of which goes to waste... aaah, skimmers) or by gradual death-dealing, The Typhoon (or even melta-flamer 'nado) is the obvious choice for the true followers of the Adeptus Astartes!