0.216 inch difference in diameter is not than significant in size or weight. Perhaps the housing (likely) is thinner thus making it lighter than a like optic.A scope with a 30mm tube is needlessly big (and probably heavy) for something like an AR. You'll likely see no advantage over a scope with a 1" tube. I don't have any idea what a Bug Buster is, but it may have features you don't really need and the glass might be passable, but it won't be great. Adjustments may or may not work well and may not be repeatable.
A simple, good quality scope may be worth looking at instead. Should you decide to upgrade later, good scopes have decent resale; hundred dollar scopes have little or no resale value.
My budget for scopes are around 400 bucks, my three main hunting rifles have scopes on them that are close to twenty years ago. Two Weavers, a 4.5x14 Grand Slam, a v-16 4x16 and a Simmons 6x18. All three have worked flawlessly, maybe I just got lucky I read all the reviews on Optic Planet, there was a bunch. 75% were happy with there purchase and all of there cons were pretty much what you all have said here. The site picture was fussy around the edges at 12x, the windage and elevation adge were not consistent. But once they got it adjusted it held zero, even when they took it off and put it back on with the supplied quick detachment rings. Once I get my scopes zeroed I don't change them unless they need rezeroed, the two Weavers stay where you but them, and I can pretty much guess hold over. I would like to find someone I could trust for a true review. For little over 100 bucks I may just give it a try, and if it doesn't work out I will put it on one of the Grandkids BB-gun. Thanks for everyone's comments I am sure you all are right.Wow...Just looked at the Leapers website...All that for just over $100 MSRP.
As an optics snob who had multiple inexpensive scopes fail me years ago, I'll say this: The more options at a bargain price = the more areas for potential issue due to cheaply made parts...In China. If you look at their warranty information, you can count out getting any (free) repair work done if your rifle falls over from being leaned up against anything. Not confidence inspiring.
Rifle optics under $1,000 are typically 'get what you paid for', with a law of diminishing returns starting around the $1,500 price point. This means that you can start to expect your features to work as advertised, and also get some good repeatability when you start making adjustments back and forth.
Not all budgets can afford this (including mine at the moment), so if you decide on an optic like this I'd recommend that you not fidget with it after you zero the scope.
Best of luck.