The first of these quibbles is quite obvious in that, while there are a number of different size replacement tips, there are no alternative types of tip. So if you're a fan of foam or single flange silicone tips, you're going to be left wanting. That said, the default tips are very comfortable and I had no problems wearing the medium sized ones (pictured) for most of a nine hour flight and the sound isolation from them is only bettered by deeply inserted foam tips. It is rather ironic that an apparently customisable set of earphones doesn't have choice in the most obvious department, though.
My second complaint is the carry case. It certainly looks like it should be useful but it very quickly becomes obvious this isn't the case (no pun intended). It's designed to carry the earphones with tips and cable attached and also has room for a spare pair each of the bass and treble ports. However, as well as the fact it is inadequate in that it only carries four out of the 12 spare bass and treble ports, it also has a peculiar cable management system.
The rubber recessed section that holds the phones flips up to reveal a cable reel arrangement underneath. However the reel is fixed to the body of the case so to wind the cable you need to either spin the whole case or wrap the cable manually. In fairness, it's not inherently difficult but is rather overcomplicated and certainly no easier than the simple 'wrap it round your hand and shove it in' method used by the likes of Shure and Klipsch. That said, when packed the case is considerably more compact than either of the above.
My final complaint is something I've already touched on and that's the spare port storage method. Ok, it's forgivable that there isn't room for all the spares in the main carrying case but the little piece of perforated cardboard is hardly a worthy backup. For a start, it doesn't even include enough holes to carry all the spares - the ++treble ports are left rolling around the box - but even if it did I would still consider it falling short. At the very least there should be enough holes for all the ports (spares and defaults) so that replacing ports doesn't require you to put down the spares mid-change - rummaging around under your neighbours seat looking for a tiny transparent piece of plastic after it's been jolted from your seatback table during a bit of turbulence isn't my idea of good mid-flight etiquette, even if said neighbour is sleeping. To my way of thinking, the ideal would be an enclosed plastic cartridge akin to the sort of thing drills bits are stored in.