I'm not a big tequila sipper (yet), but was recently gifted a bottle of 1800 Añejo and found it very nice.
More surprisingly, my wife also enjoys it very much as a sipping beverage. She enjoys her liquor, but mostly cocktails, not fruity cocktails necessarily, but she'll drink a stiff gin and tonic, not a dry martini. And the only whiskey she's ever liked enough to sip was Johnny Walker Blue, so she doesn't drink much whiskey. But this tequila goes down remarkably smooth, and, well, it just tastes good.
Along the mezcal line, we brought back a bottle from Mexico last year called Lucifer. The winemaker at Adobe Guadalupe (the talented Hugo D'Acosta), in Baja, has recently started bottling this stuff in Oaxaca for the winery. They name all their wines after archangels. It was quite tasty as well, though my wife didn't like it so much.