It's worth it just for the ability to run 1 cheap RTLSDR per control channel, which is what I use it for. I mean you can use something like SDRTrunk to scan one control channel IF your control channel and voice channels are within that 2.4mhz bandwidth limitation. Since the sites I monitor range from 700 to 860mhz, I need 2 just for one control channel. However, with DSD+ Fast Lane, you don't. So I have one SDR monitoring a control channel and another SDR monitoring conventional analog and DMR signals until and if my area switches entirely to P25, then I'll likely use my second for another site.
Now, I do think it has a few issues. Randomly my DSD+ will decide to stop scanning, sometimes it will decide that a control channel isn't a control channel anymore. And the audio quality, it sounds okay, but the audio isn't as clear as SDRTrunk in my experience and tends to miss on either the first or the last word spoken (As if someone released their radio button too early). That could also just be the radios some of the responders are using in my area, I'm not sure. Either way, most of this is only a minor inconvenience and I hope it improves in time. I leave it running 24/7 and run a rdio-scanner server for friends and myself, but unfortunately I haven't found a way to record/import analog traffic into rdio-scanner using dsd+ Fast Lane. I don't think it's possible.
So yeah, I think it's worth it. I spent $10 for the year of updates because I wasn't sure just how often the team updates the program. I'll probably buy the $25 one day but from the moment I bought it (Back around March 19th of this year.) I personally haven't seen any updates.