I held off doing the update for a couple of weeks -- I had some gigs coming up, and I don't make major changes to my equipment until I have some time to work it out if it goes south on me... Also, I was seeing all the reported problems with the USB interface and people not liking the update. I have never used the USB interface provided with the JTV -- I have 2 of them. One came with my 59 in 2011, and the second with my 69S in 2012. I always used the POD XTL, X3L, and now the HD 500 to do Variax updates. I found out you can still do the updates with the pedals, so that was a relief.
I had no problem last fall doing the 1.9 update on my 59, but my 69S took a couple of tries before it took. This time neither 59 nor the 69S had any issues and it took the first try -- whew. I did the 59 first then listened to the models and decided to go ahead with the 69S.
Overall, I like them, but saw I needed to tweak some a bit, so I got out the USB interface, loaded the software and connected the 59 to it. I built my pc a couple of months ago, and put Win8 on it. The pc has both USB 3 and USB 2 ports, but the USB 3 ports are on the front, so I tried those. Found I couldn't use my USB extension cord like I can on my Win7 machine with USB 2 ports on the front, but when I hooked up with a normal length USB cable, no problems. I actually learned this yesterday when I was setting up my HD500X.
So I hooked up the USB interface, pulled out my JTV battery (I never use, since I power my JTV's with the VDI cable), plugged in the guitar 1/4" jack to the HD500X and the JTV, and both lights lit up green on the interface. I fired up the Workbench HD software and went through the models. I used the workaround for the spank 2 position (thanks, guys) then basically worked with the tone control to get the models to my liking -- really didn't have to change much. By the way, Line 6 fixed the mid peak issue on the tone controls, so it actually works like you'd expect a tone control to work -- thanks Line 6!!. I rolled some of the highs out of the spank models, the Lester 1 position, and the noted Semi 1, 3, and 5 humbucker positions -- they are a bit harsh, but can be tamed. The Semi positions 2 and 4, the Casino with the P-90s were fine. One thing I always do is save the tone setting with the tone, so I had to go through all the models to do that. I basically did that on the 59, then saved a bundle file, hooked up the 69S and plopped the bundle in it. I checked both guitars out on the VDI input to see if there was any significant differences between what I set using the guitar input -- didn't find any.
The process was surprisingly smooth.....
My 2 cents...