It’s not one of my favorite styles, but there are definitely some better ones than Shiner. Breckenridge Brewery makes a good pretty one, Pandora’s Bock. Not sure if they distribute to you, but they’re pretty widespread. Sam Adams had one in 22oz bottles called The Vixen that I really liked, but I haven’t seen it in a while. And while I haven’t had Mönchshof Bockbier, it’s from my favorite German brewery, Kulmbacher, and I’m willing to recommend it on that basis alone.

If you want to consider doppelbocks (bocks, but stronger and richer) or weizenbocks (bocks, but with wheat malt included and also usually stronger), Kulmbacher EKU28, Ayinger Celebrator, and the classic Spaten Optimator are good for the former, and Schneider Aventinus is pretty much style-defining for the latter.