Have you used this for SMD work at all?
Kind of. I tried it before I got the blower kit and it was promising but ultimately unsuccessful, probably due to the small tip orifice. I figured it would be OK if the board was preheated, though (which it really should be).
The other problem is that the heat needs to be whacked up due to the low airflow, and that causes the solder on the tip to dry out and make a horrible mess. There is also quite a bit of pressure involved, and that causes the spring holding the collection glass seals in place to not hold them in place, so you lose air pressure...
The blower tip, not being used for soldering, doesn't suffer from that so can take the full 500C if necessary, and has a decent sized orifice. And the blower glass is a few mm longer so keeps the seals in place. It all sounds like a bit of a drag...
Nevertheless, I was using it in blower mode this weekend to do heatshrink stuff. I have an Aoyue 852, which is what I used for this before, but that's a drag to use with the thick airline trailing and the need to be careful where it's pointing when not in use.
The blower aspect of the Den-on is somewhat more useful (or not as useless, depending on your view) as it might first appear. But I would treat it more as icing than sponge, if it were a cake. If I were paying Farnell prices I wouldn't cough 50% extra for the blower facility - that would buy something like the 852, if you don't already have one, and that's much more capable and wide ranging.
Bear in mind that I haven't used a Hakko, but going from the comments on here it seems to be pretty capable. I have to say that in your position, buying from Farnell, I would probably go for the Hakko.