There are plenty of other apps available already - TouchDown [0] and Nine [1] are the two I've heard the most positive reviews about (I don't know anyone who uses Accompli).

[0]: http://www.techrepublic.com/blog/smartphones/review-touchdow... [1]: http://www.androidpolice.com/2014/02/12/hands-on-nine-is-a-c...]