Yes it would be interesting to compare it to a Jefa. Based on the specs, the Timrek is much more powerful (56dbi) than the Jefa panel antenna (13dbi).
It is weatherproof, though the panel has a small USB connector at the bottom for the cable, so I don't think it's meant to be left outdoors year-round.
What I like best on the Timrek, is that it is a full set with an adjustable stand (goes all the way up to 8 foot), so no more messing with tent poles to make your own pole. I'll be traveling again in about a month, and will give it a more extensive try for sure. Last summer I was at a campground south of Seattle, and when I asked for Wifi at the front desk, I was told that their signal was pretty weak (well, isn't that the case at almost every campground??). So most peeps were bringing their laptops to the picknick benches in front of the office, where their transmitter was. I was assigned to a site as far away from that office as it gets, and my laptop didn't pick up any signal whatsoever inside my travel trailer (most likely because of the aluminum exterior). So I put the antenna outside, aim it to the office, and was actually doing Skype conference calls from inside the trailer!