I use the Improved Clinch knot, but not on new braid or "slick" model braids. When new I used the Improved Clinch but left a long tag & tied a double overhand (granny) knot in the tag and then pulled the Improved Clinch knot closed, allowing the "granny" knot to "slip" up against the closed Improved Clinch ... which stops the knot from unraveling under pressure. Once the braid is showing a little wear, I haven't had to add the "granny" knot. Now, this was only on the one outfit that has braid & is used for casting. That braid is 10/2 PowerPro (original, not the new "slick" version). On the outfits I use for Pushing, that have 30# test braid (that's likely many years old) I just use the Improved Clinch and have had no problems with knots slipping open.
It's also of note that I don't tie braid & mono leaders together. My casting braid (10/2 PP) is tied directly to the bait. My Pushing outfit's braid is tied to a duo-lock clip which is clipped to one end of the trolling weight & the leader has a loop knot that goes into the clip I've added to the other end of the trolling weight.
I would recommend also having two things handy if you're going to be using braid : A pair of Fiskar Child Size Scissors to cut it with, and a small section of wood (like a 6" section of old broom/mop handle or wood dowel). The scissors are small enough to fit in a tacklebox drawer/pocket, very inexpensive, and cut the braid tag "blunt" ... which makes it much easier to poke thru hook/jig eyes. The small wood dowel/rod is for wrapping the braid around to pull on it when trying to free a snagged lure. I don't recommend wrapping it around your hand/fingers ... EVER ... as it can/will cut you (speaking from experience, there) !! Nor do I recommend wrapping it around a rod handle (cork or foam) as it can cut into those as well.
I have had some people suggest drilling a hole into the dowel and tying a nylon string thru the hole and one finger hole of the scissors ... making them easy to hang on your rod holders and be easily/quickly available.