crit or amp?

[locosup]

I would say to play around with your gear, chances are if you buy something for a certain price for example forci 7% samp kat or blade u will easily be able to make ur allz back.
So experimenting may take some time but atleast u know u can always make ur coin back after testing something. Amp is a great alternative to rate because it is certain where as rate isnt try get as much rate as possible whilst stacking a decent ammount of amp, then adjust ur crit damage for that extra bit of a surprise whilst in a duel.

[auctionmule]

even if you go amp, you're still gonna need to crit in order to deal damage in pvp or pve.

your bm2 will just be better with amp due to higher base attack and breaking defense easier (which can still be done with crit build).

[Luz Roja]

I perfer amp/DB just cause i like to boss alot. Feels good soloing bosses.

[cadacus_ater]

You want both....but I prefer crit everywhere I can get it, and amp everywhere else. Crit will always outdo amp when you crit, and if you have enough rate, pure crit > pure amp (assuming crits are consistent, like 1 out of 2 skills with 50 rate, or 2 out of 5 skills with 40 rate, etc. In practice such consistency isn't always the case though and this is part of the reason why some want amp forcy weps for bm2). However, cdi and amp should be balanced, they work well together.
According to damage calculations I've done, as long as you have a certain amount of rate, 10 cdi > 7 amp. Here is an example for BS 20, with damages given as noncrit + crit. The values are extreme, but this is just to highlight their differences. This assumes 50 rate total, in theory, you could figure out the kind of rate you need to make crit the better option by multiplying the crit value by your percent rate, multiplying the noncrit value by the remaining percent (100% - rate%), and then adding the two values. Below, I am comparing results based on the ratio of 10 cdi to 7 amp for the most part, such as comparing 290 cdi to 189 amp and 20 cdi

950 att vs 950 def (pvp)

*(40 amp, 240 cdi) 696 + 2437 = 3133 (240 cdi will only be obtainable by the HIGHEST cdi builds I can think of excluding pet (~190 cdi builds) + bm1's 50 dmg for BL, as far as I can tell)
*(75 amp, 190 cdi) 804 + 2413 = 3217 (this is one of the highest possible setups you could get, but I doubt many will, if any, since the build would involve double amp gears)
*(189 amp, 20 cdi) 1156 + 1503 = 2659 (this essentially swaps every 10 cdi, except for the 20 base, for 7 amp)
*(290 cdi) 572 + 2291 = 2863
Note pure crit is NOT as good as amp+crit in many cases! Keep in mind shorter, "weak" skills may have different results, but in general this trend of 10 cdi > 7 amp holds true, with enough rate. And that is my view of crit vs amp.

Extra Note: As far as what balance is best to go for, if you assume evenly matched att vs def, in theory the ideal ratio of crit damage to amp (without double amp gear) with 50 rate is something like 2 cdi to 1 amp, based on some calculations I did. That is pretty hard to follow when you have 120+ cdi though. This is part of the reason why I recommend getting crit everywhere possible and amp everywhere else: for a final build, with 160+ cdi (using 2 deathblow weapons), that is the 'easiest' setup to obtain.