Hello Robin, I use two Aigner spindle fences, the finger fence you mentioned and also the Aigner ring fence. I've worked in workshops that used a traditional, non-Aigner spindle fence, workshops with the full Aigner set up, and workshops with a hybrid where the Aigner finger fence was mated to a much older spindle moulder's own "sub fence" or chassis (the part that surrounds the cutter).
I was sufficiently impressed with the Aigner to get one for my own workshop, but I don't want to sound like a fan boy, there are definitely a few negatives.
-price, and it's not just the basic Aigner fence price, all the accessories are also pretty expensive for what they are
-weight, even with a dedicated spindle moulder you're frequently swapping between ring fence and the flat/finger fence, and the Aigner's a brute. As well as absolute weight it's also unwieldy, for example the Aigner in-feed and out-feed fences are free to float on the chassis, so they can easily flop down when you're lifting it, the fence tightening knobs just aren't man enough for the job, Aigner should really have fitted heavy Bristol levers.
-sometimes you want a traditional sacrificial fence even with the Aigner finger arrangement. Aigner have a clever dovetail arrangement which means you don't need to screw the sacrificial fence on (in fact you can't screw one on even if you wanted to), but the dovetails require the sacrificial fence to be at least 20mm thick, so all the 18mm MDF or ply scrap you find in every workshop is no good. Plus the resulting sacrificial fence is just a bit on the short side.
-the hybrid arrangement often loses a great deal of functionality, it's not Aigner's fault, but a really modern "chassis" arrangement (locating pins, dial in fence movements reading to 0.1mm, etc) just allows the Aigner finger fence to sing, where as without that it feels like half a solution
-the more open arrangement of the fingers versus a sacrificial fence means you need a beefy extraction set up, although it's no different to a standard sliding fence
On the positive side,
-I have a combination machine and the locating pin arrangement means if necessary I can remove the Aigner spindle fence and subsequently replace it without losing any settings. I hope to schedule work in the first place so that's not necessary, but a few times a year that feature always saves my bacon.
-the fingers work really well, IMO you'd have to be a bit ham fisted to bend them, they genuinely add to safety, quality, and work great with a power feed
-there's a half thickness finger at the base which is really useful, an MDF sacrificial fence can't really provide support in this area as it would just break off, and often you just need a reliable 5mm ledge along the bottom for the workpiece to ride against, for stuff like panelling with an above workpiece cutter block it's excellent
-as well as the fingers there's a little pin that can fold out to give added out-feed support where for example you've machined a rebate away. I've often glued bits of wood onto a traditional sacrificial out-feed fence to do the same job, but that feels very clunky in comparison to the Aigner
If you've got any specific questions or want photos of particular aspects just shout
Good luck!
