Gnostic: I suggest
dual booting window 7 and window 10 so you can see for yourself how good or bad it is and decide for yourself
timppu: I wonder if they have fixed the issue there was when installing Windows 7 and 8 side by side? Namely, the "fast boot" (or is it called "fast restart") feature in Windows 8 would slowly corrupt the Windows 7 partition.
The problem was detected already with preview versions of Windows 8, but at least it wasn't fixed yet when Windows 8 was officially released, because I ran into that problem as well. So I am unsure if it was ever fixed, and/or if Windows 10 "fast boot" has the same issue (if you have Windows 7 or 8 installed on another partition).
So just to be sure, I suggest disabling the fast boot feature in Windows 10 in such a dual-boot environment. It is disabled in the Windows Power Options, the option is first greyed out so you need to check the box which says something like "Show the disabled options" or whatever, then you can disable/enable that feature too.
When fast boot is disabled, then the Windows 7 partition should be safe from corruption, at least.
JMich: You can enable it on Windows 10 as well, by signing the driver.
timppu: Good to know, can you point to the instructions how to do that?
Yep, fast boot is just another gimmick of hibernating when shut down without you knowing so it boots fast.