Well, one problem with the nixon we had was the very hard bottom-out bumpers, and while they'll compress to give full travel in some situations, it takes a LOT of force and it may not jive with the overal rate of the fork, so it basically feels like bottoming when you hit this, and for most riding, you don't get full travel. It's a difference in design philosophy, other fork manufacturers give you "full travel" unabaided, and it's up to the customer to set up the proper spring rate and bottom-out feature to keep it from bottoming. As with my marzocchis, you may occasionally bottom them (clank!) when you don't have enough oil in there to help prevent bottom out (air assist feature). Easily fixable, but sometimes you don't know if you have enough or not untill that big bump/drop comes up and you find out that you bottomed it. On the plus side, once you've experienced this and "fine tuned" the fork, you can get max travel without harshly bottoming it, and the best part is that the "progressive rate" just jives with the feel of the fork, so it doesn't feel like you hit bottom 10mm from what is the claimed "full travel".
On the nixon that we got on the Giant Reign bikes (they were the "fixed" ones with less travel), we couldn't get more than about 132mm out of it, fairly dissapointing. For the "effective" amount of travel, it wasn't really any lower than my all-mountain1 set to 130mm of travel.
So you're "total travel" vrs what you'll see day in and day out may be a little different.