I have used fruit puree for a few meads now. These are convenient due to being stored in a can, easy to purchase anywhere, and they can give you a variety of flavors you may not be able to find locally. Brewing supply stores carry a variety and you can find other flavors online.
Purees are different from juices, being more concentrated and, well, sludgelike (the same consistency of baby food). My first attempt at using a puree went badly because I did not account for the sludgelike quality. I originally racked it like I normally do and ended up with just as much sludge in my carboy. I then racked and clarified and filtered to get it all out, costing me a lot of product. However, I learned from that and tried a different approach with the next puree melomel. I used a two gallon bucket and accounted for the amount of puree being wasted when I racked.
I pitched the must in the two gallons and stirred it regularly (at least twice a day for several days). I then let it settle for a day and racked into two carboys (one and half gallons). During the racking, I did not let the siphon sit on the bottom, but held it an inch or two from the bottom. This left most the sludge in the bucket and gave my mead a chance to clarify in the carboys. Yes, this does seem to waste a lot of product, but in the end you wind up with the same amount because of all the racking and clarifying one is forced to do in order to have a clear, drinkable product if you do not siphon off the sludge.
I have found that the puree does impart plenty of flavor into the mead and can create a good quality melomel. It can also be combined with whole fruit, juices, or pretty much anything! I have used peach puree, raspberry puree, and then a mix of purees and juices in different meads. All have turned out pretty well. The peach was my first attempt and is a little weak due to all the racking and clarifying I did to get clear. The raspberry – well, it is just phenomenal.