Thanks for the kind words, McT! I also read about the fretted viola de gamba instruments before I took the plunge, haha!
I did have some arco lessons with a teacher when I first got this bass, and that was very helpful.
I started out with a standard size French style bass bow, but I have been having some problems with tendinitis, and I found out that the German style fit me better and caused much less pain. It is a full size German bow, yes, this one to be exact:
http://www.gollihurmusic.com/product/1410-BRAZILWOOD_DOUBLE_BASS_BOW.html (This is the bow in the video, and the bow I still use. I have not tried any other bows, but remain curious.) I have been using Pop's rosin, but now I am trying out Kolstein, and I'm liking it so far.
Also, it would be great if you could share any other random thoughts after having had the Omni for over 2 years, such as string choices, battery life, amplification, musical situations you are in.
I have not tried any other strings than the NS Omni bass strings. It appears that it would be difficult to get "real" double bass strings to fit the bass. Ordinary flatwound bass guitar strings are supposed to fit, but I have not tried.
Battery life appears to be great (but remember to unplug the bass after playing!).
Amplification is obviously vital. Like you, I have found that my combo amp actually sounds the best. I have an Ampeg BA-115, but unfortunately, it is not loud enough for the band I'm currently in, so I mainly use my Orange TB 500 and Hartke 4x10 when I'm playing outside the house (more on that below).
Furthermore, I have found that in order to get a pleasing sound, it helps a lot to use some reverb or delay effects. I have been using either the EBS DynaVerb or the Malekko Ekko 616, not sure which I like the most.
Like you and others point out, switching from pizz to arco style is a bit challenging, with regards to turning the knobs quickly enough. I see that the recently released NXT variant of the instrument features a switch instead of blend controls, and I honestly believe that that is a better way to approach the problem. I have been wondering if I should try to get a luthier to modify my bass, but I'm not sure if that is a simple mod or not...
My main band at the moment is a technical/progressive metal band with original compositions (link in signature), so I suppose my situation is somewhat different from what most others are applying the omni bass to. Originally, I bought the bass just because I have always found arco bass and cello to be very beautiful, and after lusting over youtube videos of double bassists and cellists, while realizing that as a dad with two small kids learning an entirely different instrument it currently out of my league, I discovered the fretted omni bass and was hooked!
I used it ONLY at home for a long time, and then I introduced it (her!) to the other guys in my band. They were, needless to say, very skeptical at first, but I convinced them to try it out on a song or two.
Last Saturday I played it in front of an audience for the first time. It was an indoor festival gig, and there were somewhere around 500 people in the audience when we went on stage. I was very nervous, both with regards to my playing, to how the bass would sound over the PA and through amps that the venue supplied, and not least to how the audience would react to this instrument (the metal crowd can be quite conservative sometimes

). However, the reception was good, and I got many compliments on its sound, so now I have officially lost my virginity with this bass, and I look forward to bringing her out in front of an audience again!
I would love to continue this discussion and sharing of experience with people in this thread.