Guys if you want a real margarita, try it this way.
3 parts tequila
1 part Prunier/Cointreau/Citronge/or TripleSec
2 parts Lime Juice
tiny squirt of Agave nectar.
1 dash sea salt optional.
Seriously, I'd avoid the Rose's stuff. Yes bartenders use it the world over, but it's horrible quality, and there's really no reason to use it.
This recipe makes a traditional, very strong 'Rita, add water to dilute to taste (which I don't advocate.)
P.S. El Jimador has recently had a massive price reduction, I assume to compete with the craptastic Cuervo gold market in the US. 1.75L bottles of the Reposado and Silver are $30 in my state now, down from like $55.
This is a great bargain for a very good quality tequila, without wasting the cash on fancy bottle art. This seems to be a trend, I've seen a few other very good tequilas starting to offer plain bottles at 30% cheaper prices, which makes me happy.
P.P.S. Good tequila recommendations for the money by Te-Wa, but I wouldn't waste Don Filipe's Treasure in a rita ;)