One thing I've noticed from reading any BattleTech forum for the past few years is that, for one, people have a lot of misconceptions about the Clans, and two, it has attracted what I'd consider to be a "bad crowd" to flock to them on a number of levels - something I find unfortunate for Clan-preferring players who don't fall into that category (of which there are many). It seems like many people take their own ideals and concepts ranging anywhere from anime space samurai to nazi rhetoric and try and apply that view onto the Clans. Hell in the last week I've seen everything but the hilariously bad throwing around of the word of "honor" to the veiled suggestion that someone on this very forum wishes the clans were real so we could kill all morbidly obese people. I've noticed there's very, very few (by comparison) people who prefer Inner Sphere who tend to steadily push their in-universe faction politics onto forum discussions about the game, or anything else. In short, I'm hoping anyone who might be entirely unwittingly giving Clan players a bad name might at least listen to a few points here.
I'm going to address a couple of the really common issues here.
Zellbrigen and it's purpose - This is the number one issue, and the source of all the people who attack things like legging on a "THAT WAS DISHONORABLE!" level rather than, while I'd argue it, gameplay level. You have to understand a few things about Zellbrigen: It was created to preserve equipment, so it would be salvageable after the fight. If facing an enemy unwilling to do this, the Clans will have no problem at all about calling it off, either. What's this mean? Under Zell, legging a mech and disabling it would preserve the majority of the chassis and would, in fact, be a very honorable kill. Likewise, it'd also spare the pilot's life so they could make a good bondsman - another issue people forget about. So from an RP standpoint, legging = dishonor has absoultely zero basis in the canon.
The clans are all about Warrriors and nothing else, they were all born in test tubes! - Another totally inaccurate assessment. It's true that some castes were in fact engineered for that purpose, but there's two major points everyone seems to miss: There's a large amount of Clan MechWarriors who were either freeborn or not born to that caste (though treated as second rate), and a huge and thriving civilian population that are not among the warrior elite, and may support the military, but are not military. This includes many washed out (the majority of engineered pilots wash out) MechWarriors, who once out of the "warrior world" often find they don't, in the end, miss it. Their civilian population views things like freeborns much more kindly, as many are. They have artists, musicians, merchants - everything you'd find in the InnerSphere. This also means there's a huge range of people living on Clan worlds that are just as imperfect and varied as IS worlds.
The Clan sense of honor is not like our sense of honor. They are not Samurai. - The Clans have a lot of rituals that are based in their honor code, like the Batchall and the graduation by fighting. But anything that we would deem cheating, sneaky, or exploitative is viewed as savvy, pretty often, in Clan canon. Things like technically lying as much as possible during negotiations, ganking your own teammates to graduate with a higher rank and so forth are not considered wrong by the Clans. In the case of the latter, it was viewed as a stroke of tactical genius to gun your graduating class down in the back. That was not, I repeat not, a villain. On top of that, you can outright murder dozens of people and if you can prove your tactical worth, you can get off for it. There's a reason the Clans and Draconis Combine thought they had the "honor" thing in common at first and quickly found out that they really didn't. It's a highly alien concept.
.. in short? Please, if you really plan on throwing around "Clan this, clan that, clan honor!" in any kind of quasi-RP sense, read their horribly messed up political history and any fiction written before Btech writing took a horrendous nosedive (Everything after the civil war starts, IS or Clan, is painfully out of character with everything before). Just because you don't like something doesn't mean it's somehow unfitting with canon.