This is not a criticism of Polarkernel, who is doing a great job. It is just an answer to the question.
Compared to Stackexchange
The site is noticeably slower. This can surely be fixed with code optimization, perhaps to implement the recursive edits of the tags in the system in C, rather than in high-level language like PHP, as I presume it is done now (this is the non-paranoiac reason to share the source code). Hiding and unhiding, for instance, can take a long time--- several seconds, it is instantaneous in SE. This is not to fault Polarkernel who implemented a tremendous tag-system in a way that looks bug-free.
The notification system of SE's is simply the right way, and our way (list of question style things) is the wrong way. But this requires some serious UI effort.
The main serious issue is the requirement of doing all administrative voting on the dedicated pages. While this is necessary sometimes, "vote to close", "vote to move as off topic", and "flag as spam" should appear as stand-alone votes attached to threads, so that they can be done automatically by the community, not requiring constant administrative oversight.
Compared to Quora
The main "wow features" of Quora is that every discussion was fully threaded hierarchically, and could be viewed as a tree. This is a feature that is difficult to implement efficiently, but Quora did it. The reason to do the same is because tree-structured comments and discussions can be moved at the top node directly to another spot, or linked in a heirarchical way, like a filesystem. This is useful when the site is enormous, but now it is not necessary. Also, it is not a request for work from Polarkernel, again, it is just a statement of fact.
It also remembered everything you typed, so that if you left an answer half-written, and you came back two months later, it would still be there half-written. If this is done client-side, this is great. If it is done server-side, it is a massive breach of privacy, as it requires every half-baked thought to be transmitted to the server. I think Quora does it server-side, as a purposeful breach of user privacy, but we obviously can't do that, if we want to implement it. So perhaps it is best unimplemented.
Where we are best
The editor we have is simply better than SE's or Quora's. We have better MathJax support than SE, which would take forever on long pages (now it's better), and we do not run into slowdowns at large file-sizes like they do. The Q2A editor was always a delight, especially that Polarkernel added preview and auto-preview (thank you).
We also implement hierarchical tags, which makes us head and shoulders above SE. This is the main feature we have that nobody does--- the ability to organize content by field and subfield indefinitely deeply. This feature will become more central with time, as we are able to offer folks the ability to target their own narrow specialist interest, both in reviews and in Q&A. It is of course not obvious that this is useful now with such a low number of users.
Regarding the question
The look and feel may be tweaked and optimized rather easily as compared to the guts. It is better to look a little uglier and get the guts right (as we have done) than look flashy and have a rotten inside.