I wouldn't worry too much about the dust collection when making my purchasing decision; you can always change that. FYI My experience is with a ShopBot (standard, with router) router and with an industrial sized (26,000 lbs) laser cutter.
The number one question, "What are you going to be doing with your machine?" Removing quantities of material or removing lines or both? The engraver that you have listed looks like a solid production machine that is perfectly suited for engraving. It doesn't look like it has the setup to do production wood v-carving or routing. If you want a machine that is versatile, I would defenitely suggest looking into the ShopBot desktop unit with a spindle.
I don't think that you should compare a $14,000 machine with a CNC Shark. I don't know about the newer versions of the Shark, but the first generation machines looked VERY flimsy. And, while Rockler is a great catalog, they are not known for their industrial quality.
The two biggest challenges that you have when using CNC is designing your product, and holding it still while it is being processed. With a laser such as an Epilog, your second problem doesn't really exist. You put the part where you want it, press start, and voila!!
With a router, not only do you have to make sure to hold down the part you want to keep, but all of the scrap that you generate. If you cut a 3" hole in a board and don't have tabs, vacuum, and/or screws holding it down then my suggestion is that you duck.
Another difference between laser and router is that with a router, you have to deal with tool pathing and post processing. Which is where you tell the program that you want the router bit to travel around the INSIDE of the circle that you've drawn so that you end up with a 3" hole not a 4" disk. Also this is where you tell it to leave some tabs to prevent the 4" disk from becoming a 4" discus. Post processing is where the software converts all of those lines that you drew and toolpathed into x,y,z points.
So what is the laser engraver's comparison, once it is setup, it can be as easy as clicking "print".
I realize your question wasn't about lasers, but hey, I was on a roll. That's how the politicians handle it, isn't it? If you can't answer the question that was asked, then answer the question they didn't ask.
If your business plan involves production engraving, get a quality production machine with good support. If your plan involves versatility with fine resolution, than I would recommend looking into the ShopBot desktop. It is a very rigid machine with quality components. ShopBot has been making low cost CNC for 15 or so years and has GREAT customer service. It doesn't matter if you by your machine new, or you're the 5th owner, tech support is free and located in Durham NC. You can take their 2-day class in Durham (I highly recommend). There are a bunch of tutorials on YouTube. Also there are various group events around the country to network and get to know your machine a little better. Generally these "camps" are more helpful for the new owners. Also, not many of the machines have an online usergroup that is as helpful and thorough as
http://www.talkshopbot.com/forum/
Don't forget, when pricing your setup to include the cost of the CAD software. For the price of the one engraver, you could afford Two of the SB desktop units and good 3-D cad software.
PS For when you do look at ShopBot, if you can swing it, I recommend an Alpha with a spindle. If you can't afford both now, you can always upgrade a router to a spindle later, but the stepper motors are another story.
