I chose the Dagger Approach after a fair bit of research and consideration. I wanted a kayak to use on creeks and rivers that have a variety of flat and moving water (easy whitewater). I have used it in a variety of conditions (a river that was Class I whitewater, a creek that was Class I-II+ with a few challenging spots, and several lake outings, one of which was a very windy day with swells and whitecaps on the lake). I have liked it for all the applications.
The skeg works quite well for tracking considering the length and lines of the boat. The bow does plow a bit of water in the waves, but not miserably so. I have not used a sprayskirt with it yet, so understandably took on some water in the cockpit in the rapids on the creek and on the windy day at the lake. The back storage hatch remained dry. On the windy day at the lake, some waves were breaking over the bow, but I only needed to sponge it out occasionally, whereas a fellow paddler in a Pelican Pulse 100X took on so much water that his boat "swamped" and capsized.
As far as speed, it is relative to expectations and intentions. I'm sure I would not be able to keep up with a group of experienced sea kayakers in 18-20 ft. boats, but for our group of relatively new paddlers in ~10-12 ft. flatwater kayaks, I have to hold back and circle back to avoid getting too far ahead of them and have chosen to paddle this kayak with the group intentionally to disadvantage myself a bit.
My back hurt a bit my first paddle, so I played with the seat adjustment. I moved the backband forward by unbuckling the straps to the back of the cockpit and tightening the straps on the back of the backband. Then I had to let out a loop of strap from the buckles to get enough length to hook the straps from the back of the cockpit into the seat back. That improved the comfort of the backband a lot for me.
Overall, I am very pleased with this kayak for the purposes I selected it.
Admittedly I'm too large for the boat at 6'1" and ~170lbs., but it snow plows like crazy on flat water and I don't see how that would change with a smaller, light paddler. It has a drop-down skeg which is nice for tracking and it handles up to Class II rapids OK, but if you want a boat that does any single thing very well then look elsewhere.
This is a good, stable platform for someone new to paddling who wants to paddle a mix of flat water and flowing water but it will quickly be outgrown.
I will echo what one other reviewer said. The sprayskirts made directly for the 10.0 are not a good fit on the 9. They are loose from the start and will get looser. I have been searching for a proper sized skirt and so far, only Immersion Research has confidently indicated that their Shockwave in XXL will fit it on the loose side and the XL on the tight side. I have also had good luck with Shock Wave, so I'm asking them for more info as well. I'll update once I've gotten a skirt that fits!