The aesthetics are interesting.  The red fret markers and side dots are nice touches.  White markings just wouldn't work.  A white version with black markings was also produced, and that looks pretty good as well.

The absence of a conventional wood body makes it less resonant, but this changes the tone and makes it more sterile-sounding.  That doesn't make it the perfect bass for most people, I'm sure, but it gives you an interesting sound to work with, especially if you use effects liberally.

One nice feature is that the Rail does not require double-ball strings, unlike Steinbergers*.  There is a clamp at the headstock that can be screwed down to hold them in place.  Unfortunately, it is hard to clip the strings flush to the surface, so there' is always a sharp bit at the ends for you to cut a hand on if you grab it wrong (This isn't likely while playing, thankfully.)  *Note: There is a string adapter for Steinberger guitars and basses that allows the use of conventional strings.

A new pickup almost certainly couldn't hurt.  I'm just not impressed with the tone here.  Maybe with the right combination of effects...?  I don't know.  I have a Peavey BAM 210 Bass Amp that gives you models of eight amps and eight cabinets to work with in any combination, but I haven't been happy with any sound for it that I've yet discovered.

The absence of a tone knob is a huge drawback for any bass for all the obvious reasons (unless all you do is slap/pop stuff; even then you would still do well to vary your sound if not your technique).  Apparently the oversight was realized and a tone pot was added on later versions of this model.  There isn't room for a basic preamp, let alone controls for a multiband EQ, so modern bassists may have little use for The Rail beyond the gimmick of its design.  I hope to at least add a passive tone knob to mine when I have a chance.

Technically this is more of a repair than a mod, but when I received the bass, it was missing the thumbscrew (and knob) that is used to hold the pickup section in place along the rails.  Since the volume knob was simply one of the common barrel-style metal knobs, I used one of those I had on hand to build a new one.

First I matched the threading of the hole with a very long screw, probably about 4" or so.  Remember, the screw had to be long enough to go down the shaft to the rail as well as upward into the knob.  I then bought a handful of nuts that would fit the screw.  I put these on shaft to create a solid portion.  The nuts were a little wider than the diameter of the shaft of the knob, so I bored that out with a drill to accommodate everything.  I assembled the combination of screw, nuts, and knob, and screwed it in to see how much longer the screw was than I needed, then cut the screw down to the desired length.  Finally, I (or rather, Dani, my partner) epoxied the screw with nuts into the knob.  There... good as new!