My assessments/educated guesses:
It probably behaves similarly to the BearVault in regards to transparency and large opening — both big plusses in my book as one who has used the BearVault a lot.
Weight: okay, so adding the canister portion (21 oz), cross bar (1 oz) and lid (6 oz), it comes to 28 oz IF the weight listed on their website is accurate. If you add the frying pad lid (yes, there's an optional lid for the lid that's 2 oz), then you're at 30 oz. My BareBoxer on my own happy li'l scale is 26.7 oz.
So, weight difference is nothing. cut off a few tags and leave out a few peanuts and raisins. Unless you want the 2oz Lid Lid.
BearVault BV450: only $47 at CampSaver if you wait for one of their 20% off deals. Weighs the most (33 oz on my scale), but opening it is easy and no need for tools.
BareBoxer Contender: $55 + $12 shipping via their website ($12 shipping is steep for the weight). Lighter than BearVault (26.7 oz on my scale), opening needs a tool, but more compact than BearVault. It fits nicely in my Granite Gear A.C. 60 and I would imagine in smaller pack quite well.
Lighter1: $85. I'm REALLY curious about how easy it is to open and close. Can't find anything (yet) that explains it. It looks like at least 2 screws that hold the crossbar in place. That would mean, I'd assume, a tool is necessary to open it.
NOTE #1: The Lighter1 claims 300 cubic inches with a 7" diameter and 9" length. The BareBoxer claims 275 cubic inches with 7.4" diameter and 8" length. WIth just those measurements, it's 344 cubic inches to 346 cubic inches, so all I can figure is that the plastic is thicker and/or the curves are more pronounced on the BareBoxer to give it that much less volume. Or that nice big opening on the Lighter1 is part of the equation.
NOTE #2: I've found that the more narrow, the better. So in theory, the Lighter1 would be beneficial, however it is 1 inch longer than BareBoxer, so it might really stretch a narrow pack if packed horizontally.
NOTE #3: I've found the price differences aren't worth caring about for something like this: get the product that is best for your need, the $20-40 difference will be long forgotten in a year.
If weight is most important: BareBoxer (26.7 oz). Then Lighter1 (28 oz or 30 oz with Lid Lid). Then BearVault (33 oz).
If easy access is most important: BearVault wins. No tools. I've never had any problems, even if I've had to take off a glove for 5 seconds on the coldest mornings. BearBoxer needs a tool, Lighter1 has at least 2 Mystery Screws.
If cost is most important: BearVault wins. Wait for a C@mpS@ver 20% special, you can get it for $47.
If transparency is most important: TIE between BearVault and Lighter1.
If wide, easy access is most important: TIE between BearVault and Lighter1.
If smallest diameter is most important: Lighter1.
If largest volume (of the three in question) is most important: BearVault.
If length/height is most important: BareBoxer.
If having a built-in frying pan (with our without Lid Lid) is most important: Lighter1.
For me: I'd be intrigued by the Lighter1, but I'm wary of how it opens and closes, it's 1 inch longer than BareBoxer, it's 2 oz heavier and it's $20 more expensive. So for me, I'll stick with my BareBoxer.
But if you like what you see with the Lighter1, go for it. It's light, small, semi-affordable and keeps bears from eatin' your twinkies.