Assault squads decreased in points cost, but no longer come with jump packs. When jump packs are added, they come out costing the same. This has the effect of making their transports cost the appropriate amount (rather than being discounted when taken for a small squad), and I'm not sure why it didn't work this way before. Beyond this, they've gained the option to take one eviscerator for every 5 Marines. Basically a two-handed chainfist, the eviscerator gives the squad some excellent tank killing ability. More importantly, it allows the Assault squad to take some extra specialized close-combat weaponry, something they desperately needed. A full squad can have a power fist on the sergeant and two eviscerators, allowing them to take on much harder targets than before. While they're still not a premiere assault unit, Assault squads are now able to take on heavy infantry, rather than just bouncing off like they used to.
Scout Bike squads gained WS and BS 4, just like basic Scouts. Other than that, they're still the same, so strictly better than before for the same price. Maybe we'll see some on the table now.
Bike squads didn't change at all. However, Attack Bikes dropped 5 points per model when taken either as part of a Bike squad or Attack Bike squad. The most important change is Mounted Assault, which now allows any Independent Character mounted on a bike (not just Captains) to unlock Bike squads as Troops. In addition, there is now no minimum size for counting as Troops, so expect to see lots of 3 strong Bike squads with 2 grav guns and a combi-grav on the Sergeant.
The Land Speeder Storm is now Fast Attack choice, but it still counts as a dedicated transport for a Scout squad. It's 5 points cheaper, and the Cerberus launcher is now S4, so it may actually kill something. It also increased to BS 4 to match the increased skills of Scouts, and the assault cannon upgrade became cheaper. All in all, a lot of good improvements.
Land Speeders also dropped 5 points a model, and their secondary weapons all dropped 5 to 10 points in cost (except the typhoon missile launcher, which was already the best option). When taken in squadrons of 3 Speeders, the squadron can move an extra 6" when moving Flat Out. Again, this is a useful points decrease. The increase in speed won't be useful most of the time, but could be useful for a late game objective grab. When taken as part of a Demi-Company, Land Speeders are Objective Secured, making this a decent strategy.
The Rhino, Razorback, and Drop Pod haven't changed at all in their rules or costs, but they can now be taken as Fast Attack choices in addition to their roles as dedicated transports. This means that if you want to take a Drop Pod for your Centurions, you no longer need to take allies to do so.
The Stormtalon Gunship has the same base cost and statline, but its secondary weapon options all became much cheaper. It lost the Escort Craft rule but gained Vectored Afterburners, which allow it to move an extra 6" when Zooming Flat Out or gain +1 to its Jink saves when Hovering. Honestly, Zooming flyers move fast enough that you'll rarely need the extra 6" and a Hovering Stormtalon will die quickly even with a 3+ cover save. Overall, it became better just because its weapons upgrades (which are essentially mandatory) dropped significantly in points.