the best way to know is to do what "unleash me" said.....................Its only when you compare with a CDP that im not too sure of the extent of "good" ( in this case)
Magma, nice summary. Agree with everything you said in this post.
However, in your previous posts, I could not understand why you are emphasizing so much on the importance of room acoustics to someone trying to decide to invest in a DAC or not. In my observation, room acoustics affects speakers mostly and to some extent the rest of the chain. Also, there is no point investing in a DAC just because a huge difference was found while listening using a headphone setup. At the end of the day, it should sound good in the OP's setup where everything else remains the same (room treatment et all), otherwise there is no point. It depends on the entire chain rather than just room acoustics.
On another note, the whole thing about room acoustics, tweaks etc is very subjective and we as an audiophile community are a confused lot

. For Eg, sometimes we say, the speaker stands improves the way the bookshelves sound. After a while, we ask ourselves "do we really want to listen to the speaker or the speaker-stand combo":lol:? Sometimes we call a characteristic sound of a speaker/cable/component as a signature sound - in a positive way and sometimes we term it as coloring - in a negative way based on our state of confusion.
I agree with Stan's POV that a well designed DAC irrespective of its price should definitely improve the way a system sounds given that the system has "not so good" electronics. Whether the improvement is worth the $300 spend is the big question? In some systems, the difference may be day and night and the $300 spend may seem less for the improvement that was heard. But in some systems, for example in mine, my Marantz CD63SE was doing an almost equal job when compared to the digital out from Marantz into Caiman, so the $300 spend may not be justified in my rig.
First get the opinion of a few people as to what is lacking in your current system sound wise. Only get the DAC after you have an idea what it is that you are trying to solve.
So Abhi, like Stan, Magma, unleash_me and everyone has suggested, the best way to find out if it will improve is to borrow a DAC and try in your rig. Then decide.