If you ask the question here- the answer is EE
If you ask the question at Hammock Forums- the answer is Hammock Gear.
As you said-
HG doesn't offer all the ground sleeper functions you may appreciate (well done and several generations of use/feedback padstraps for ground use)
HG does offer a slightly more radial cut bag (like a Katabatic Gear) which is a nice feature in colder temps.
EE has their proprietary baffle system, which many feel is superior to a traditional baffle style (like HG or UGQ)- although that's a personal opinion.
If you don't want to play with your down as much- EE is better at reducing down movement (but still movable)
If you do like to shake or pat your down to the sides, or top to adjust the warmth- HG is better for that.
EE offers 0, 10, 20 options
HG offers 0 and 20- but you could overstuff a 20 a hair as that's an standard option they offer.
Other than that- you'd probably need a bit better apples to apples to compare finer details and it may simply come down to lead times.
Both are quality bags from solid cottage guys... In theory; EE comes from a backpacking background and HG from a hangers point of view- but Tim at EE hammocks and the guys at HG backpack so ...
I like EE's shell material better than Dutch's Argon .67... but I like RBTR Membrane 10 best (like the Momentum fabric from thru-hiker)
UGQ uses Membrane 10 in their stuff, but the lead times are pretty high there too-
http://www.undergroundquilts.com/renegade/default.html
If you want to spend some big bucks-
http://katabaticgear.com/shop/sawatch-sleeping-bag/
This is newer cottage vendor who makes some very well cut and thought out bags for a western traveler. Those who use them love them, but I'm not one of them so hard to say. For a true cold weather quilt though- might be one of those once in a lifetime buys that justifies the cost.
If you have a wide pad (large xtherm) then you will likely not miss the pad strap kit as much as someone on a narrow pad if that helps any.
Somebody above mentioned sleeping cold in an EE bag in Colorado...
Regardless of the bag you choose; any flatlander jumping in to a higher elevation trail will suffer from the elevation change on a few fronts. One of the problems encountered is a tendency to sleep colder than normal by a 5-15 degrees until acclimated, so plan accordingly. Until you've done it enough to know how it affects you- hard to evaluate a bag's performance when the heating element is the only faulty equipment.