The first thing that I noticed upon taking this out of the box is... this is a beefy little unit. It feels solid and well put together.
This model differs from other portable/mini CO2 regulators in a couple ways. First, it has a gauge and you can set the pressure. Second, it takes relatively large 74g CO2 cartridges. These cartridges give you the capacity to dispense two full 5 gallon kegs. The 74g cartridges are the equivalent of 4.625 16g cartridges. This is convenient and it also ends up being less expensive. Current pricing from Midwest Supplies makes the larger cartridges about 17% cheaper when purchased in two packs vs 16 gram cartridges.
Portable Serving/Small Space Regulator
I think that the typical use for this would be as a regulator for portable serving or as your everyday regulator when you don't have a lot of space.
After using it for a bit, I'll propose a couple of additional uses.
Backup - I'm out of CO2 and I want to pour a beer!
I pulled this out of the box, when I did, because my 20 lb CO2 tank was empty. I didn't have time to swap it out and I wanted to serve a new pale ale recipe that I recently brewed. This came in handy in a pinch. My initial concern was that this would not fit in my deep freeze kegerator, but as you can see there's plenty of room. Since I can hang on to the partial cartridge, I'll swap my tank out soon and I won't end up using much CO2 from the 74g cartridge.
Serve Beers at Alternate Carbonation Levels
This regulator goes up to 30 PSI. That's plenty to serve high carbonation beers like Hefeweizens and Belgians. If you don't have a dual or triple pressure setup, you could use this regulator to serve beers at higher pressures. I would not suggest force carbonation with this unit. The 74g cartridges would get pricey. You could carbonate using your existing regulator or just as easily naturally carbonate with priming sugar.
Saving Partial Cartridges
This particular unit comes with a gas ball lock disconnect and a 74g CO2 Cartridge. A good thing about this setup is... you don't have to discard partial cartridges. If you decide to serve a 3 gallon keg for a get together, or use this to serve beer from your kegerator in a crunch, you're able to save the rest of that cartridge for a future use.
For size comparison, 74g cartridge next to a 16g cartridge. Each 74g cartridge can serve up to two 5 gallon kegs.Here is the fully assembled unit next to my handheld injector. The mini-regulator is superior to the handheld injector. I've found that the handheld injector tends to eat up cartridges at get togethers. Other attendees tend to squeeze this for fun and sport. The mini-regulator takes care of itself and keeps your beer at a constant pressure. Plus.. the bling factor, you have to consider that.
EDIT: Homebrew Finds Reader Jason mentioned that these can be adjusted so that they sit more horizontal. Horizontal orientation + rotating the ball lock puts the regulator right on top of the keg. Perfect for tight spaces.
The Leland Mini Regulator is well built and has worked great for me. I'm looking forward to having it for upcoming Summer parties and as an emergency backup. I think it would work well for someone who wants to keg beer but is short on space and I also think it would be handy to occasionally serve beers at higher carbonation levels.