I don't know if better alternatives exist because it has just been rock-solid for the last 12 years that I've been using it. I've used it in multi-monitor and machine desktop setups (e.g. an Apple laptop paired with a Windows desktop and linux desktop for enterprisey cubicle development), as well as to let me drive my gaming and media PC from my couch using an Apple laptop.
I was a bit bummed that the pricing model went from free-as-in-beer to free-as-in-speech, but couldn't be happier to pay $10 for a lifetime license.
I feel it belongs in this thread because even when I've neglected to upgrade various machines, or upgraded OSs on machines with the application installed, it just continues to hum along. I can count on one hand the number of times I've had to deal with any problems in any capacity.