Had a bunch of Modulus basses over the years as well as a Steinberger. The only drawback I noticed with the early ones was that with no truss rod the neck relief would change with string gauges and what you got was what you got. I believe Moses has always used truss rods and the later Modulus instruments had them as well.
Yes, my 2004 & 2008 Quantums both have truss rods, however I rarely need to tweak them and it was 4 degrees this morning when I woke up. Going to be mid-40's tomorrow and I almost guarantee the necks will be straight as a board even with the dry / cold weather.
The "Sterile" Modulus sound is dominate but I've found I can get a great, organic tone especially from my semi-hollow bodied Q5 with Bartolini pups and Aggie OB3.