Hmmm ok then... but I still have a feeling you won't be convinced. Anyway I'll share my story:
Well I was born and raised in France, where AFAIK there's no such thing as "grain-fed beef". Keep in mind cows are supposed to eat grass, not grain. So to me, grass fed beef is the norm, and grain fed is an exotic variation to the norm. I understand that for most Americans it's the other way around.
When I first got to taste grain-fed here in the U.S. I immediately noticed two things:
1) The grain-fed beef taste has a little bit of a nasty, gamey note to it. Not bad-nasty, more like a cheese can be nasty, or like fish sauce can be nasty. A good nasty. But still, nastier than what I had been used to.
2) The grain-fed beef texture is much more tender than what I had been used to it. I'm not just talking filet mignon: even a rib eye steak for example is much more tender than the grass-fed "entrecotes" of my youth.
Now back in France I have never, ever had frozen steak, or vacuum packed steak, or mail-delivered steak. I would go to a proper butcher and ask for the desired cut, which would be wrapped in paper, brought home and cooked. I have never, ever noticed ANY nastiness or off smell to a grass-fed steak unless of course it had been staying in the fridge for too many days, then the smell would indicate the meat was spoilt and we'd throw it away.
I would describe the taste of the French grass-fed beef I've had as CLEAN. IMO that's a better way to describe the taste, and a good way to compare it to the grain-fed taste which IMO is more DIRTY (even if it's a good dirty). What I'd have trouble describing or explaining in a thread is how the grass-fed beef can be simultaneously cleaner, subtler and yet have actually more taste than the grain-fed. It's IMO a cleaner, more distinctive, more focused, more elegant taste, if that means anything to you. The grain-fed taste is more dirty, less "polite" and more primal. Grass-fed is well mannered, well spoken and to the point, with a bit of an artistic side. Grain-fed is a bit rude, loud spoken but knows all the good dirty jokes.
In fact I've noticed after eating a lot of grain-fed for a while, I tend to think of grass-fed as lacking something. Much like after drinking a lot of Napa Valley wines for a while I find the French wines to lack something. I have to get reacquainted with the subtlety of the French taste before I can appreciate it again. There's something "in-your-face" about California wines, the same way there's something in-your-face about grain-fed beef.
Grass-fed is also much leaner, and also tougher. That means that one, it cooks much faster, and two, it benefits from cooking much less. So you really, really want to reduce the heat and cooking time for grass fed. I have posted my instructions for a good grass fed steak in another thread here, but it's almost like sushi: flash fry for 30 seconds on each side and eat with a little bit of butter. The meat in the center is raw and cold. Much like you'd prepare a venison steak. If you prepared it medium-rare it would be overcooked.
So personally I like both, and they both have their place, but I tend to eat more grain fed when I'm in the U.S. and obviously only grass-fed when I'm in France (no choice there). And like I said I also tend to prepare them completely differently.
IMO if you find anything nasty about the taste and/or smell of your grass-fed beef, that means something is wrong with it.
Edited by French Fries - 2/28/13 at 4:36pm