It's simple. You audition an amp with the headphones you use. If it sounds better, it is. It may not be the penultimate compared to what other people have heard, but it is a step up, as audibly proven during the audition. In time, one may find something better to power their K340. As stated, if one doesn't have access to the better stuff, one can't claim to know anything better. Ignorance is bliss, unless you want to gamble and buy an amp unheard based on internet recommendations. That's why trying to force feed someone an opinion doesn't work, except for the sheep. In the end, good is subjective, after a certain plateau which is also subjective. My ears may tell me that your good is my best as I may not be able to hear differences beyond what you are stating. I don't own your rig, for instance, and I probably never will. I've made a decision that I will never buy an amp, just build. If I can't build it, there in lies my limit and probably 99% of the market.
The arguments being stated about experienced people making posts vs. newbies making similar posts can be summed up in one sentence. I found it on the internet, so it must be true. That applies to everybody, and in many ways it's the same, be it a newbie or an experienced person. The arguments can be made that one is posting what they know, but the truth generally is that the newbie nor the experience knows all. The only way to know for sure is to hear the rig yourself. What the rig is, is going to be based on reflections of what people found on the internet, an unfortunate circumstance of a niche market. As such, I guess those impressions are the truth at that point in time for that person making the statement. Neither newbie nor experienced are fully wrong, nor fully correct. "OMG, Zana Deux w/ HD600 is the best." "OMG, Tomahawk w/ HD650 is the best." "OMG, <insert amp> w/ <insert headphone> is the best."...yeah, sure, whatever. OMG, broccoli w/ cheese is the best.