Vader is probably the best example of someone who mastered djem so but he is a beast. If you are not physically strong, should you use soresu?
So far so good...so far so good...
I think everyone is missing the point of the question. I am asking if djem so is worth using in lightsaber combat if you are not a powerhouse. Not if power is the deciding factor in a sword fight or if agility is more important.
When i watch rebels or any ot movies, it just seems like everything vader does is based in djem so. Yes he mastered all forms but djem so is the form that counter acts soresu(obi wan was a soresu master and was his biggest failure in combat). Vader is a power house and djem so seems to be his wheel house.
Exar kun would be great. I think vaders ultimate fight would be Mace Windu, mace uses vaapad and is obviously ruthless in combat. Its up to debate whether he got the better of palpatine or if palpatine was using him to manipulate anakin(i think its both) Mace would be the ultimate match for vader.
http://www.imdb.com/list/ls063670214/