This 4 1/2 star overall rating for Synergy is such complete BS! I paid for a couple of Synergy upgrades throughout the Tiger years and all I ever got from it was frustration and a lot of wasted time. It only worked between boots if you loaded it manually. Now version 4 has been released and it ACTUALLY WORKS this time. Problem is, you're forced to buy it yet again if you want to use it with Snow Leopard. Who can say that it won't break again in a few weeks if you buy it and the developer's record of fixing the non-loading bug is abysmal. Plus, like the other commenter pointed out, there have been practically no significant feature additions. SO, Wincent has this little operation going on, forcing people to buy Synergy over and over again, if they want to keep it working, except that, in my experience, it almost never worked and this lazy developer isn't even decent enough to offer a discounted upgrade price for users who paid for the aggravation of twinking and testing various tricks to coax the previous versions to perform as advertised. Besides these major flaws, Synergy is a great concept, and very useful if only it were a reliable utility and the developer would treat previous paying customers right.