VM solution with "seamless" features

I'm currently using a VM to run Visual Studio on Fedora. Because I want easy access to both systems at once, without having to minimise a VM or use hotkeys to access the host system, I require a VM solution that has "seamless" integration - I.E hiding the virtual desktop, and running applications in the VM as though they were running natively.

Virtualbox has this solution, but it is somewhat unreliable and doesn't maintain seamless mode (or multi-monitor mode) between boots. VMWare has a feature called "Unity mode", which seems to be a little more reliable - however, unity mode has not been a VMware Linux feature since v7 - we are now somewhere around v17.

I'm using v7 at the moment, but I'd like to find something that won't fall over at some point in the future. RemoteApp isn't a solution, because VS needs to be able to launch a browser and communicate with it during debugging. What other VM solutions have this "seamless" functionality?