For overall efficiency, you want to maximize heat transfered to the pot. The most efficent I could ever do was about 4quarts per ounce. But, this typically took more time and strong winds would interfere. Field conditons are MUCH different. I expect closer to 3quarts per ounce in the field at about 13 minutes per quart. On HIGH you can expect 2 liters per ounce. I will note here that these specs are under rated by at least 20% or are WORST case tests, indeed 90% of campers will do better out of the box. (I bought three of the newer verions for the kids, all did better.)
Heating Power vs Efficiency is a typical trade off. Higher powers, such as with the XGK, will boil quicker, but the efficiency suffers. (Liters and quarts are very similar in size.)
The boil time is WAY faster at 3.5 minutes per liter. BUT, you only get 1.5 liters per ounce! These are true ratings but are BEST case tests, typical for MSR products. I used this stove a couple times, but like the old Simmerlite, Nova, and Whisperlite, could not cook on it, it burns too hot and went through a LOT of fuel.
Note that these have similar burner styles. Again, for winter use, I would choose the SVEA for groups of two. For larger groups, up to four, I would choose the XGK or similar higher output stoves. Don't get tied up thinking I am married to a SVEA. I have been searching for a replacement since I got the bloody thing. It alwys struck me as being rather primitive. But, it is just the lightest stove for the cooking I do, the lenghth of trip I am usually on, and has a small volume including fuel. Even esbit does no better, and fares MUCH worse in colder conditions. Alcohol is just hugely inefficient with fuel. Canisters fare no better than alcohol, except for the on/off valve. Being carefull with fuel, I can make a 10oz weight of fuel last 2 weeks with the SVEA, boiling water twice per day and cooking. The STARTING weight is all I am interested in, because my weight invariably reduces as I go. It has low emmisions, does not soot up pots, and, has super reliability and durability.
Having high power outputs I see as a detriment. Others feel differently. I don't consider waiting an extra 4 minutes for coffee that important.
For winter use, yes. It is still a viable stove. It depends on your group size, though.
It does polish up very pretty, but I havent done mine in a few years. I'll have to do it before tommorrows trip... It makes a good reflector for the tea light candle when filling out my log.