+1 on the Mighty Mule, mine from Tractor Supply on sale, with additional components from Amazon:
FM350 Gate Opener
FM121 5 W solar battery charger
FM137 Digital Keypad
FM138 Wired Vehicle Sensor
FM143 Automatic Gate Lock
FM135 Single Button Entry Transmitter
FM132 Push Button Control
I didn't keep track of the costs, but I bet after all's said and done, it's not far off what someone quoted for the Apollo.
I made my own gate using 2x2 thin wall steel tube, and made up ball bearing hinges so it opens/closes very easily. I estimate the gate weighs about 300#, right at the limit MM says that the opener is good for. I hear it strain every time it starts or stops the gate, but it doesn't seem to be doing it any harm.
The wired vehicle sensor isn't reliable after the ground is saturated with water; I probably shouldn't have buried it a foot deep. And I'd put a 50' lead on it instead of the 25' I have now.
The MM has been working well for the past 5 years, but it only sees a half dozen cycles a week. I'm using a WalMart deep cycle marine battery charged by the MM solar panel, and have never had a problem with a low battery.
Programming in opening codes and other things is a bit of a PITA through the digital keypad. A cell phone or laptop interface would make this a whole lot easier, but that's probably a big buck feature.
I have two neighbors that also use MMs, and I haven't heard any complaints from either one.
One of these days I'll be adding another fence, and it'll probably get another MM opener.