Is it risky to upgrade from Windows 7? Sounds like sonar will work fine. What about everything else? Waves, jamstix etc? Can I expect any software that works in 7 to work in 10?

 Upgrading anything is risky.  Create a drive image.  Then update to 10. 

Acronis. You should be backing up to external hard drive every week or so. One day you might thank yourself. Alternative is to learn the hard way.

The main issue is drivers, check out other threads for further info.

Ta

All my plugins work so far, including Waves, IZotope, MeldaProducrion, IKM, Native Instruments, Softube, Antares AVOX4, all the Cakewalk plugins about 950 in total.
I've only loaded them into an existing project and played it a bit.

I upgraded my daughter's laptop to 10 and all seems fine. I know my version of Paragon (11 home edition) isn't supported. Paragon 15 is. I'm going to look into Acronis or something else before leaping into 10, but it seems to be a smooth transition for most.
 I wonder if the Seagate dashboard thing would work with my Seagate external drive? I'll be looking into it.

mudgel
All my plugins work so far, including Waves, IZotope, MeldaProducrion, IKM, Native Instruments, Softube, Antares AVOX4, all the Cakewalk plugins about 950 in total.
I've only loaded them into an existing project and played it a bit.

you have to reactivate anything ? that is my biggest concern- vst will report back to HQ and I lose the vst for exceeding allowed installs and no more activations left.

I upgraded to Windows 10 Pro yesterday.
The only problem I found so far is that Raxco PerfectDisk 13 did not work or uninstall.
I bought the new Perfect Disk 14 and ran the cleanup tool and it seems to be OK now.
I have started Acronis 2015 True Image to see if it works (it does), but I have not yet made a Win10 image.
I'll do that when I get the settings adjusted as I like them.
 
I opened Sonar (Foxboro), Live 9, and Soundforge 11 and all seem to be OK.
 
I haven't done any recording yet...

the only thing i've had to do since letting the auto upgrade do its thing is reset my default browser to waterfox :)

Remember you don't need to boot into windows 10 if you have an acronis recovery disk. Before updating to win10 I recommend creating one of them.

The Start Menu is currently limited to 500 items — and every single link inside the classic Windows 7 Start Menu counts as “one item.” This could cause real problems for upgraders since the same database that holds the 500 items to display, also controls search results. This means that if you install applications 501 – 510, hit Start, and start typing, they won’t be found. If you’re building a fresh system you won’t run into this right away, but if you’re upgrading from an older OS, you almost certainly will. At the moment I have 510 items in my start menu.