So I've opened both sets... Some thoughts on both:
-People will definitely feel the Imperial set is the bigger value... The Rebels get a new anti-vehicle artillery piece (Radar Cannon), which is outstanding, but the Laser Artillery Tower is simplistically designed and constructed, and I can easily see people being much happier with the perceived value of the Imperial's set giving you a big assed AT-ST.
-The Hoth Rebel Trooper Variant is glorious, but goofy in a way too. He's really a great figure in every way of course... He's the Rebel Trooper we all wish we had more of since he's the basic infantry grunt and not the support gunner with the repeating blaster. Still though, his helmet is funny because hasbro cast it so the goggles are see-through, even though they're up on his hat... so, basically, you can see through his hat. That's kind of weird.
He's a pretty flawless generic Rebel infantryman though, and it sucks Hasbro isn't giving us this guy on a Legends card.
-The Hoth Rebel Trooper Repaint is pretty glorious too though... All these army builders Hasbro makes are generic, yet somehow distinctive, and they could easily repaint any of them I think, and resell them to us. Hasbro gives you a standard rifle for him as well, which is the new sculpt Dak is toting around. It's a nice complement to the repeating blaster he comes with too since I know I have a lot of that gun and not enough of the basic rifle.
-The Laser Tower is indeed a simplistic large accessory, but I still love it. It's pretty right in scale, it has the opening door and hatch... It's a better paintjob than the UBP release a while back. I love it. They included a sticker for the inside of the door now too, by the way. Kind of neat, though stickers are meh to me.
-The Anti-Vehicle Gun (Radar Laser Cannon) is a 100% new sculpt, and it's NICE! Tons of detail in it, far superior to the original modern incarnation of this artillery piece. There are two flaws though. It doesn't have the tank tread bottom sculpted on it, and it doesn't tilt up/down like previous versions. That's a little disappointing. It's more accurately scaled though (a bit larger, actually), features a cool accurate sight thing on the back, the silver panels on the radar dish thing are actually sculpted an d painted now, and it even features two opening panels on the back to expose the electronics inside the main assembly of the gun.
It's a good bit better than I imagined. Add to that, that it has an ammo/power box now that connects to it with a flexible hose, and it's really cool. Even the ammo box thing is so neat I wish I had a dozen of them.
-K-3PO is the Build-A-Droid sculpt... He feels kind of flimsy, but he's not a horrible figure. IMO though, they should've added a repaint of the Variant Hoth Rebel Trooper. A blonde or black haired Trooper would've been nice, maybe with a white or dark brown scarf deco.
Either way I would've gladly taken another Hoth Rebel over K-3PO. Even an update to Riekean or Derlin would've been cooler. Maybe even a generic officer for the trenches? K-3PO was a pretty lame choice. How many versions of him are there now? What a weird figure to have so many incarnations in plastic.
-The Imperial set, again, is the one I think people will value more. The AT-ST alone makes the set really pop. It's a big, poseable, super awesome pack-in.
-The AT-ST has a sort of simpler deco than the Endor version, on one hand, but on the other hand it has added details the Endor Walker just lacks. All the gun barrels for instance are painted black, giving them some added realism for sure. There are a couple added silver details in the cockpit. The cleaner deco may appeal to some collectors more than the Endor's more dirty and grimey look.
It's molded in a lighter plastic too, giving it that added clean look to it. The darker grey spray detailing on the body stands out more on this walker as well. I think many people will want this one over their Endor version, should they only want one walker on the collection shelf.
-The Imperials are a nicer deco as well... Many people will like these Snowtroopers over the Legends figure currently available, or previous decorations of the Imperial Snowtroopers. He also sports the new more narrow stance, which is nice of course.
-The AT-ST Driver is really the only new thing in the set. He's a bit tall, features a removable helmet that's smaller than the AT-AT Commander's helmet (I think), and he too features goggles that cannot be put on him over the helmet as they should be. They're thick, and when on the head, they flare the helmet out in a goofy way.
He is a bit tall though, like I said. I'm surprised Hasbro would go to the trouble of a 100% new sculpt for a figure that they have the base already available for in the Scanner Technician. He has a ball-jointed torso, which is cool, but all they needed to do was give him new forearms for the gloved hands, and a new head, and the Scanner Technician would've been perfect.
I'd take an army of this figure though. Oh, and yes I think the straps he comes with are intended to be the seatbelts of the AT-ST "in real life", but for some reason Hasbro gave them as an accessory as part of the uniform. The weird thing is, they are in EU materials as a web-harness for backpacks and other gear, as the AT-ST driver is the basic Imperial Army Trooper's uniform/look, and the web gear is part of that. Maybe it's Hasbro throwing a little fan wank to the EU folks into that stuff, such as myself? I dig it.
-Much like K-3PO in the Rebel set, I would've probably preferred to have something OTHER than a tri-pod cannon. The E-Web gun is very overscaled compared to what it should be in the films. I can't tell if this is a 100% new item or a re-used sculpt. I'm pretty sure it's at the very least mostly re-used. Something about the handles on the back seems new to me, but I could be wrong. They replaced the accurate projectile at the gun's barrel too, which completed the previous release's gun, with a "blaster fire" projectile. This leaves the tip of the gun inaccurate, actually.
Either way though, I'd rather had another figure in place of the tri-pod gun, or some kind of equipment, or something they made up like a rocket launcher, or even a 2nd AT-ST Driver with a different hair color. *shrugs*
My final verdict though, is that both sets are pretty cool. As a Rebel fan, I'm partial to the Rebel set... As a figure/toy reviewer though, I think the Imperial set delivers the bang for the buck! The Rebel set is more like a playset, and it's simpler/less "mobile", and the big pieces may not be that exciting to many people for the $40 price. I mean, the other set has a friggin' AT-ST folded up inside it!? That's pretty slick.
Happy hunting though. These are two of the cooler modern items coming out for the line in 2010 I think.