racerx, Ipe is definatley harder to work with than composite (Trex), but not that bad. You will want to allow more time for labor. This also come with a 25 year warranty. I was going to do this deck in composite (Timbertech). I would have had to close the joists to 12' on center due to the 45* angle pattern, not necessary with the IPE. I used 5/4 x 6, which is good up to 24" O.C.. The 1 x 6 (3/4 true) is good for 16" O.C. Ipe seems to have all the benefits of Trex with the exception of working with it. I've seen some 10+ year old Trex decks and was not that impressed in the way it ages.
Ipe costs a bit more than composite. $2.69/linear ft. 5/4 x 6, not sure what the 1x6 costs.
Here's the wood I used, check out the specs.
http://mataverdedecking.com/index.html