Scissor lifts are difficult and prone to breakage is the problem. Whenever it is possible to use a different style of lifter, I would do so.
However, scissor lifts are pretty good under a certain set of circumstances- if you need to achieve a lot of extension, but retract to a very small height.
Now, the reason most teams are using winches is because once you lift your robot up-
you need to stay up.
I would expect that if you were to lift yourself up with a DART, it would backdrive as soon as the match ended, and you'd end up below the climb level. I could be wrong, however, so don't necessarily take my word as gospel.
Some ideas I would check out if I were you are the WCP 2016 MCC:
http://www.wcproducts.net/mcc2016/
They use a telescoping arm and have quite a bit of documentation on how you can do the same.
Additionally, I don't know whether or not your team has decided to go under the low bar, but if you didn't, then climbing is pretty easy, as you can start at 54" tall and you need to reach up to 76" to climb.
If you have any questions or anything, feel free to PM me or ask more questions in this thread.