I spend a lot of time playing with a laser cutter (120w generic from China). A lot of the things that they talk about are quite cool, but I think that they do not show all the other parts that also require time and effort - although I do imagine that one of their value propositions is that they remove and/or simplify a lot of the processes and their complexities. One of the biggest issues I currently have is to generate a file that the laser cutter will like - it has to be a dxf with no sub layers or any linked files, or a old illustrator file (.ai version 8). Each "settings layer" has to have it's own distinct color, and sometimes if the colors are too close, they get merged into one. It can also be difficult to set the correct distance between the things that you want to engrave and the things that you want to cut - say you want to engrave a round logo on a round beer coaster: getting this perfect would take a lot of tweaking, as there are minor (yet visible) gaps and mis-alignments.
Next, to get the laser to cut properly also takes some tweaking. It's almost impossible to get a repeatable cut, since there are so many different factors that you need to take into play: the location of the item you're cutting on the bed, the temperature of the laser, the thickness and quality of your material, the accuracy of the auto-focus, and the settings themselves. If we look at the location for example, there is a huge difference between the top left corner - where the laser mirror is - and the bottom right corner. On one side your material will catch fire, on the other, it will only cut half way through. The material is also an important factor - if the material is even 0.2mm thicker on the top compared to the bottom (especially true for acrylic), then the laser will go through on one side, and won't go through on the other. For wood, tiny differences in it's quality can have a significant impact on the cut and especially on any engraving you do. With wood and similar, easily smudged materials, you also have this sort of 'caramelisation' after you cut and engrave - the degree of this effect depends on whether you used the right power or not (for which you also have to take into account the location, temperature, material quality,...). If you try to clean it off by hand or with a dry tissue, you will smudge it further and it will be difficult to remove. Instead, you have to painstakingly clean every piece you cut with an alcohol soaked cloth, which will remove most of these smudges - however it won't remove any burn marks. As per the burn marks, you get a lot more of them when you use a honeycomb bed compared to one which has a number of thin pieces of metal that stretch across with a few cm interval. The glowforge laser has this honeycomb bed, so expect your wood, cardboard and paper cutouts to have some of these burn marks if you don't pay very close attention to the power/speed of the cut. With plastic, getting a cleaner cut is a bit easier, but the fumes are horrendous. Also, if you don't cut through the whole thickness of the plastic the first time, and do another pass, the edges which you cut will have these 'micro-cracks' that dont' look very professional. Similarly, if you cut with too much power, your plastic edges will just melt and look quite bad. However, an advantage with plastic cutting is that you can clean it without too much difficulty, if you use sufficient alcohol you can get most burn marks away.
Engraving looks really nice when done with a laser cutting, but it does take some time until you figure out the correct settings for each material. I particularly love engraved plastic and wood, the result (especially from genuine, extruded plexiglass) is beautiful and vey professional. A local public figure has had a picture of him holding a laser-engraved logo that I made him as his profile picture. Personally, I made some laser cut business cards, and they have absolutely blown away a lot of people - one person even told me that he stuck it to his wall for inspiration. I've also worked on laser cut tags/tokens that I give out as a promotional gift to people, and then they can use it as a fidelity card when they order things through my startup. I'm still working on perfecting these tags, but they required a lot of testing (over 30 different attempts just to get the QR code to engrave in a readable way), and I still haven't been able to generate them through software (right now they have to be put into illustrator before exporting them to the laser cutter). Lastly, engraving paper will likely incredibly difficult. On their page they have a sheet of paper that they engraved - I want to know how many attempts it took them before they got it to work - especially since the paper gets very easily caramelised. Maybe they had to use a special coating or used yellow/blue painters tape?
Despite all of this, laser cutters are extremely cool. The one we have cost $4000, and people have done lots of amazing things with it. Nowadays, you can get a 40w laser from ebay or aliexpress for a few hundred dollars, but do expect to spend weeks figuring out how to use it. The Glowforge looks like a pretty cool idea, however I don't know if they'll be able to survive at this price point + with the technology being at the state it is today. Their software (minus the part where it's cloud based), looks really powerful and very useful.