First off, let me say that I have been a huge fan of the Force FX Lightsaber line since its inception, and for years, I've watched the collecting community ask for removable blades, so to finally have them in my hand at Comic-Con was truly exciting. Hasbro had both of the new sabers from removable-blade wave 1, Anakin Episode III and Vader Episode IV.
Initially, these look and feel the same as their non-removable-blade Force FX counterparts. The hilts are made with the same quality of materials, the blades feel just as secure. I didn't get out my calipers or micrometer to check, but the hilts seem to be the same size as the previous versions. There is no visual cues to suggest where the blades are removable from. Ep IV Vader's saber had 1 small missing detail, looking into the collar where the blade meets the hilt, inside the original Force FX saber there used to be a notched ring, this ring is now smooth in the new version.
Blade removal differs from saber to saber, and seeing it in action explains why this idea cannot perform swappable blades. On the Anakin saber, removing the blade is as simple as unscrewing one of the small knob detail pieces near the top of the hilt (it's an existing knob on the movie prop, Hasbro camouflages each saber's pin differently tailored to that prop), sliding out that screw-pin, then pulling out the blade. The bottom of the blade is a notched plastic black ring with 6 or 7 electrical connectors at the bottom which align to pins inside the hilt, as the blade houses the LED string as well as motion sensors.
The Vader saber, however, requires unscrewing the hidden screw-pin, removing the entire shroud (the black collar at the top), then pulling out the blade which has a different sized anchor at the bottom of the blade to fit this specific hilt shape and work with the shroud better. So in order to get the blades to fit as cleanly and hiddenly as possible to each of their hilts, they are tailored to work with just that hilt design. I suspect swappable blades won't ever be possible mainly because each screw-pin has to be in a camouflaged position unique to its hilt design based on the original props - accuracy will trump modularity.
Removing or replacing the blade creates a buzzing click sound from the hilt. With the blade removed, attempting to activate the saber creates a "short circuit" sound from the hilt. I felt this made sense since the blade couldn't be extended from the hilt; however SirSteve felt differently citing the logic that the movie universe doesn't need an acrylic tube sticking out for the hilts to make sound, citing the logic of the user's imagination. Both lines of thought seem sound to me, perhaps some day Hasbro will include a hidden switch to give the user that choice.
The sabers are $10 more than Hasbro's last run of Force FX sabers bringing the line to $120 each. The removable blade technology has of course added to that cost, but Hasbro has included some extra elements which carry the price quite well.
First off, each saber now comes with a plastic belt clip, Vader's has a black box with a hook, while Anakin's has the prequel-era Covertec-style disk clip box, and both work quite nicely with their respective sabers (I didn't try it on my belt, but Hasbro designer Mark Boudreaux - who is heading up this Force FX line - wore the Vader clip on his belt during the convention).
Beyond that, each saber comes with a plug to close the hole left by the missing blade which is sculpted and painted accurate to that saber's bladeless movie prop design. Hasbro explained it as collectors not wanting crud getting into the open hilt, I liked it from purely an accuracy perspective, so form and function go together here.
Finally, the last addition was a change in the display stand functionality. The clear left and right arms that used to hold the sabers now have 2 notches, a small and a large, and these arms can be reversed so you can display the hilt ahead of or behind the removed blade, or you can alternate big-little on either side to display the complete saber as before. Not only is that a simple yet clever feature, but it maximizes your display options. And in the back of the base, a door has been added so the belt clip and hilt plug can be stored inside the base.
Some final notes, Hasbro had these pretty much ready to go last year, but due to last year's slow sales on existing Force FX, they had to hold off production until now, but Hasbro believes the line will do better, and collectors will eventually want to get these. Hasbro's SDCC display had 2 upcoming removable-blade sabers, Obi-Wan Episode III and Darth Maul's. Obi-Wan's looked pretty much the same as the existing version, whether that's good or bad is still up to personal tastes, I like that Force FX over the Luke ROTJ version despite them being quite similar. The Maul looks nearly identical, the collar below the emitter plate seemed to be a different color than the metal hilt which differs from the existing one, but I'm not sure if that's a prototype issue or the requirement of plastic for the removable blade. I did however check to make sure that the removable hilt will come with the connection battery hatch so it can be married to the original Maul Force FX saber to make a single-bladed double saber without shelling out maximum coin.
So far, I'm quite impressed with these new removable-blade Force FX lightsabers, and I plan to get either the Vader or Anakin in the next month. I don't think I'll replace my entire existing collection, but if Hasbro continues to make new sabers, I'll certainly pursue those; and if they keep the existing ones around, perhaps I'll slowly replace my collection over time.