I was mainly getting at onimaru, which should go for a nice few 100k? Alternatively you can sell hagun if you think you can increase your total damage by more with the gil you'll make (and just use onimaru in the mean time). Onimaru to hagun, according to a guy in another thread (horrible, I know), is around 5% increase in damage. As for myself, I wouldn't ever sell an end-all piece but rather farm for the remaining gear first. However, this depends on your playtime and stuff, if you want to increase your damage now upgrading gear with hagun gil might be an option.
Anyway, critical hit grip is +3% critical hits. Pole strap is 2% double attack. Therefore, roughly, pole grip increases damage by 2%. For crits to achieve that, your PDIF needs to be quite low (e.g. for PDIF of 1, a crit doubles your damage, so that's a 3% increase). The cutoff point is therefore 1.5 PDIF, above that pole grip wins. However, this doesn't account for weaponskills: every WS can DA, not every WS can crit. Even if a WS can crit, DA can still contribute more damage (again, depending on PDIF).
Easymode: use claymore grip if you're not getting minuets or meat or so on high-defense stuff.
If you're talking about brave grip, it increases the damage of a critical hit: an entirely different story. Basically, its only use is under the effect of mighty strikes.
Thread's a day old, but I have to say it.... don't sell your Hagun unless you're retiring your Sam. At least... not right away until you know for sure why you want to. There is a reason why in the past two years since you played, the Hagun is one of the few AH items to actually cost more now. That reason is that parse after parse unequivocally conclude that it is the best GK you can get on AH. People without one may say that it isn't. People without one may say that it's overrated. Hell, maybe even some people WITH one will say it's overrated. I know it's fun to think about spending all that money on stuff. But until someone comes out with a valid parse that proves otherwise, Hagun is still king, and you're stronger for having it.
I always thought it was overrated. I still bought one. It's the bomb. I was an alchemist in the days when you could make a mil a day from powder and oil.
I'm certainly not selling it.