"Worth it" is entirely subjective in this case. I definitely think the Basic models are "worth it". It kicks the living snot out of a Surefire L1, in a smaller package. And compared to pocket rocket lights like the Amilite, the ability to use a lower output, with extended runtime, is a major benifit. An HDS Basic might be 2x the cost, but you get more than 2x the flashlight.
As for the Ultimate series, "worth it" becomes much more divided. I personally think most of the extra capabilities are excessive. SOS, strobe (too slow to be used "tactically") locater beacon, etc only serve to make things more confusing. However, some of the features make it "worth it" to me. I don't own an Ultimate yet, but I will once the 85 is rereleased. I plan to set it up with 60 lumens primary, 30-40 secondary, 10 low, and 85 as the high. I also like that you can set it to work momentary.
I suppose it comes down to a choice between simplicity and a myriad of options. With something like the McLux PD, you simply push the button or twist the head. It just turns on. You don't have to click, double click, tripple click, double click+press+hold, or anything like that. You just turn it on. I wouldn't even think of handing an Ultimate EDC to someone without turning it on for them first. Anybody can figure out a PD.
I'm rambling...
Whatever light you get, you simply can't appreciate the usefulness of multiple levels of light (even if it's just two) until you use one. Be it an HDS, a PD, a Jil Intelli, or one of the Surefires. There is such a thing as "too bright". I can't see myself ever buying any light in the future that isn't multi-level. Otherwise, I'd be forced to carry more than one light. Well, I guess I already do carry more than one light, but you know what I mean.