Let's get the lame duck out of the way first.
My limited experience with Castle Rock has not given me a favorable impression of the brand. Years ago, I tried their $10 Pinot Noir on a whim. It tasted like grape juice steeped with pine cones. Stemmy, acidic. Bleh. I didn't drink it. Finally, six years later, my patience had grown back. "Cheap Pinot is very hard to make not disgusting," I told myself. "Perhaps they'll do better with a Zin." I was expecting it to be jammy and too sweet, especially at only 13.8%, but at least drinkable.
No. It smelled hot and tasted insipid. Extremely acidic, with tight, bland fruit. It tasted in no way like a Zinfandel. How could it? How hard do you have to work to suck that much flavor OUT of such a delicious grape? Especially at such a low alcohol content for the varietal. Granted, it was my first ever Mendocino Zin. Perhaps it doesn't ripen in that cool climate - at all. My husband observed that it would be better off called "Rando's Red" than advertised as a Zinfandel. I poured my glass, and the bottle, down the drain. You can skip this one.
Now, the Simi Zinfandel I opened next that night (I wanted Zin with my burger, dammit!) was a significant improvement. For starters, it smelled like a Zin, with aromas of brandied plum, blackberry jam, and spiced rum. It also tasted like a Zin, with a palate that reflected the bouquet, accented with nicely balanced acidity, and lovely tannins giving it a satin mouthfeel with a long, spicy finish. Great deal for the $8 I paid on sale. At the regular price of $18, I'd go with Seghesio, St. Francis, or Cline. But for under $10, put this one in your face.
A month later (yeah, I know, I need to update more) I was ready for another Zin. I decided to try out one of the new ones from work that had been winking me in the face - a $10 Old Vine Zinfandel by Four Vines (California, 2008, 14.6%). Violet-red in the glass, it smelled of bright grenadine and red cherry. A promising Zin-like aroma (I swear, that Castle Rock traumatized me). The palate was richly fruit forward without being sweet, if not terribly complex. Though it did have a nice sort of dark, musty finish of mushroom and oak. Not bad. Not great. But not bad.
Of course, that being said, we did drink the whole bottle, which doesn't always happen. Its lack of oomph, rather than making it boring, just made it a highly drinkable background food wine. I don't think I'd buy it again - in the same price range the Bogle Old Vine Zinfandel is far better - but I don't regret buying it, or opening it. It was nice. And might even make a good starter Zin for someone accustomed to more traditional varietals.