For about 3 years, I've used VMWare Fusion. It is amazing. I've always been a fan of VMWare's products because they have snapshots, suspending, etc. However, I was even more impressed when I installed Fusion on my Mac.
- Snapshots, suspending, etc. (Fusion Feature Page)
- Supports Windows 7 (and every other version of Windows including 8.1, XP, etc.)
- My MacBook Pro has only 4 GB ram (OSX, from 2011)
- Windows inside the virtual machine is responsive
- OSX (host) is responsive
- It has NEVER crashed and I reboot Windows about once per month
- true integration, not just a guest OS running inside a host OS. Really impressed with the integration between OSX and Windows. I was used to using VMWare to run Windows inside Windows (for testing) but with Fusion it is really like having the best of both worlds. I have some apps which only run under Windows and use it for that.
They offer a free trial but I'm sure you will love it.*
- I know it sounds like I work for VMWare but I do not. I am just really, really happy with the quality and functionality of their software.