The Avett Brothers (upright bass, banjo, acoustic guitar, cello, kick drum & snare played by the feet of the brothers) are brilliant. I was turned on to MaS by a fan of The Avetts, so I thought it would be appropriate to mention them here. The most common link between the two bands, besides the instrumentation, is the ability to write heartfelt and soulful lyrics that do a great job at capturing your attention and holding it. Try the Emotionalism album to get a good idea of what the band is like.
The Devil Makes Three is another old timey style acoustic folk band that uses similar instrumentation but takes on a more upbeat, bluesy tone; they really make you want to get up and stomp your feet. The lyrics are genuine and genius as well, but are much darker/comedic than The Avett Bros or Mumford. The new album and song by the same name, Do Wrong Right, are incredibly amazing.
Blitzen Trapper is excellent as well; they use vintage equipment to garner a classic rock sound, and the harmonies are brilliant. Try the Furr album or check out the gigantic library of free concerts they have online.
I almost forgot to mention the other common link between these four bands, the beautiful ability to harmonize. It's organic and genetic in some cases, the way they all blend their voices together. Try any of these guy and you will not be dissapointed. It's so rare to find an album where there is literally not one bad song to be found; these bands and the new Mumford & Sons album defeat this issue with the aforementioned recommendations.
Do any of you in the UK have any suggestions of similar UK/European/or other country's bands for us over here across the pond?
Thanks in advance...