Yeah, I hear ya! I don't have as many years yet, been 25 years for me- but enough that I know what it feels like to rediscover what a guitar can do, and be pleasantly surprised. I just bought my JTV59 sunburst last month, preceded by only a couple weeks by a new DT25 - have had the HD500 since 2010.
I am still on the fence, in terms of which 'firmware' sounds better- mine came loaded with the first iteration, 1.71 or something. I played it a few jam sessions, then updated to 2.0. Definitely a difference, though I hadn't spent enough time with the previous versions of the models to notice a substantial change in sound.
I think of like this - the pre-2.0 firmware models are the end of the line for the previous Variax guitar and pickup models. 2.0 represents the very first "HD" offering of their Variax guitar models, so it can be assumed there will some issues - there are many, many threads on here of people battling back and forth debating the merits of each.
I just didn't want to get stuck "liking" the old firmware, I figured eventually the new firmware will be updated again, and I'd rather build on the progress rather than be stuck in the past versions. The new acoustic guitar models sound stellar!
Going VDI to the HD500 then Studio/Direct is quite a nice, noise free, clean and pristine sound. In terms of functional, practical notions-I can say, do quickly upgrade your VDI cable to something with shielding on both ends. The VDI cable that comes with the JTV is designed for connecting the guitar to the included USB interface box, and only has the XLR style shielding on one end.
Line6 makes their own brand, and you can get it at Guitar Center, Musicians Friend, etc. It's decent, but it's not great. Some other kind folks on here pointed me toward Best Tronics, out here near me in Illinois. Their cable is far, far superior - it feels and looks like a proper instrument cable, it's made in the USA, and only ends up costing a few bucks more than the L6 version. They make them by hand in small batch, and their turn around is very quick. I bought one from each, so now I just use the L6 cable as my backup.
here is what that BestTronics cable looks like: