It's worth pointing out that good as Dominos are (I have both the 500 and 700 so I'm pretty committed) they're not perfect for everything,
1. The standard beech dominos rot quickly in damp conditions, so aren't much use for outdoor projects or exterior joinery. There are sipo dominos for exterior work, but that's more cost and because they come in uncut lengths it's an additional time element
2. The domino mortice is actually deeper than stated, about a mill at the corners and about a mill and half in the middle (it cuts on a sweep), so be very careful when plunging into material that's close to the limit
3. Dominos aren't particularly versatile when it comes to referencing from fixed surfaces. It helps if the project is designed around the limited reference stops that the machines offer. But in the real world this is rarely the case, which generally means you end up cutting more "sloppy' mortices than you'd ideally like, leaving voids in the workpiece.
4. Festool wanted to put locating "pins" on Dominos, but ran into a patent dispute so were forced to switch to paddles. The original pin models had the huge advantage of taking slip on spacers, but also the disadvantage that they sometimes pop out and foul an edge when you least want it!
5. The perspex window does not come calibrated...you absolutely must do this calibration yourself or the machine won't fulfil its potential. IMO Festool should emphasise this more in the literature and give clearer guidance on how to complete this (but when has Festool documentation been anything but basic?).
6. Dominos swell and shrink according to humidity, so it can sometimes be a pig to disassemble after a test dry glue up. But you'd be crazy to trust to a glue up without a dry run, as even very experienced users get caught out with tiny misalignments that need individual dominos paring down to fix.
7. Unless you're using a domino regularly it's easy to get it the wrong way round or otherwise mess up a project, at least with a more traditional approach the workpiece is fully marked up so catastrophic mistakes are a bit rarer.
8. A domino joint is only as good as the accuracy you've been able to achieve on the components, there's not much point getting a domino until you're certain that you can consistently produce components that are dead square and dead straight.
Bottom line for me is, much as I love my domino machines, I wouldn't be without a biscuiter, a dowel jig, and even a traditional morticing machine...they still all have their roles. And for many woodworkers the money a domino machine costs might be better invested in a more accurate planer/thicknesser or a more accurate saw, after all these are the basic machines that you need for pretty much every project where as there are plenty of cheaper alternatives to a domino.
