I own an 18x Sport Ultra (kevlar) of the generation before the current models that have the retractable Track Master rudder.
I am a mid-60s intermediate paddler, 6'0" who struggles to stay under 180 lbs but who stays in decent aerobic shape. More than 90% of my paddling is for fitness and takes place on a small reservoir on smooth water. The most challenging conditions I have faced since I bought the boat in August of 2008 have been 2-foot wind waves on larger lakes with a longer fetch than my local reservoir, though once there were waves that high on the local lake because of 40 mph gusting winds that kicked up a fuss despite the small fetch. I have not done any camping in the boat. I've been paddling since 2004, with a Venture/P&H Easky 15 and then an Eddyline Nighthawk as my previous two boats. I also currently own a Current Designs Scirocco.
My boat is light, easy to carry, about the 36 pounds advertised by Epic. It is pretty fast--considering its aging engine. When I'm in shape and conditions are mostly calm I can sustain 5.5 or 5.4 average speeds (GPS measured) over an hour and a half of fitness paddling. The GPS tells me that I can sprint to 7.1 mph. That's with Epic's mid-wing paddle. By way of comparison, the same paddle and effort and conditions in my plastic Scirocco gets me about a 5.1 mph average. I've paddled one race of 11-12 miles on northern California's American Estero and led the other novice paddlers (a dozen or so) by 20 minutes or more at the finish--official time 2 hours, 10 minutes. Even the Intermediate and Expert paddlers, on surf skis or outrigger canoes, (and on whom I had 10 and 20 minute starting advantages) did not catch me until about 2/3 of the race distance was covered.
The rudder on my boat hinges the trailing portion of the hull and includes a molded-in tab that extends below the normal line of the bottom of the boat in give a better bite. The tab is a compromise that Epic scrapped for the newer retractable rudder. My rudder makes the boat track very well in most conditions, but is not really all that good for strong directional control in following wind and waves. The carbon-fiber bar and pedal control system at my feet is durable and effective for both knees-together full-body-rotation paddling and for knees-apart-and-locked-in paddling. The latter mode allows control by edging to which this 18-foot boat responds quite well. Even if a rudder line broke, a moderately skilled paddler could readily control the boat just by edging provided the rudder did not get locked over on one side or the other--not as maneuverable as my Scirocco, but way more maneuverable than other 18-ft boats I've tried, e.g. the CD Solstice.
The two major failures of my boat's design are the seat and the rear hatch. With the seat I had problems like those described by Celeste De Bease below. I do rolling practice each summer in the nearby college pool, and the single track holding the seat to the hull broke because the seat constantly rocked from side to side and eventually pried the track apart. Also like Celeste I had a very good response from Epic, whose representatives paid for the repair even though I was the boat's third owner and it was well beyond warranty. It did take a long time to get the new parts delivered to the local dealer and for the dealer and their repair technician and me to all get together. The work was completed in December, and I didnít start roll practice again until the next June. The new track held well enough, but the seat itself tore at the point of its front attachment to the track. I expect Epic would have worked with me again in a satisfactory manner, but I chose instead simply to take out the seat and go with a homemade system of Thermarest camp mat and closed-cell foam that has made for a comfortable and lighter seat that lowers the center of gravity maybe half an inch. I do surrender adjustability, but I'm not a paddler sophisticated enough to notice the difference. The rear hatch looks and acts like it was not designed for its seat. In a 20-minute rolling drill at the pool, it lets in a half gallon or more of water that I must sponge out each time before carrying the boat back to my car. For this problem also, it appears, Epic has designed a solution in its current generation of the 18x and 16x.
Overall, my Epic 18x Sport Ultra is still my 'pride and joy' and gets used nearly every week. I find myself wishing I could upgrade to Epic's newer version of this boat, but Iíve spent my big bucks on water toys. I'm happy I did.