You
can. But the question is if you
should. Build 10149 may be faster and indeed more stable than its predecessors, but being a technical preview there still are risks. That fewer, so far, are experiencing serious issues doesn't mean that issues won't come later on, either in this build or going from this build to whatever OS version.
Have a look around the forums, e.g. in this
10149 Bugs Thread and this
1520 "Gone Bad" with the 10149.
I'd rather be consistent with Microsoft's advise on not installing technical builds on one's main device.