I switched from Autodesk cam products to solidcam's inventorcam back in march, and I've been really happy with the purchase. The posts are a bit rough initially, but the support that solidcam does give with a maintenance package is excellent and quick to address any issues. If I'm struggling to get something to work, I can call tech support, and some guy will remote into my PC and walk me through it. The software is really stable thanks to the processing methods it uses; more often than not, inventor will crash before solidcam does.
The technical advantages are where solidcam shines through. Solidcam owns the patents on dynamic milling. It's the only cam system using the material's ultimate tensile strength and cutter geometry to calculate stepovers, speeds and feeds, engagement angles, cutter loads, etc... At the end of the day, it makes programming challenging parts and materials a breeze. My milling spindles sit at the same load 100% of the program as the feed rates and stepovers change constantly. It's impressive. They also calculate the cut's ACP (axial contact points), which I've found to be hugely helpful if I'm doing something sketchy or getting poor tool life. Overall, it's one of the most powerful and intuitive cam systems I've ever used.
The other thing I like is the ridiculous amount of training videos they have. I purchased training hours when I bought the software and never used them. Between the free online training courses and the tech support guys, I've never found myself struggling to figure out how to do something I've never done before.
I've used Esprit, Powermill, Mastercam, Fusion360, Inventor HSM, PTC Creo, Featurecam, and NX. Solidcam is hands down the best bang for the buck. I would choose solidcam over Mastercam any day of the week.