Hello audio masters! I need your expert recommendations on this one.
 
Please allow me to give you some background. I'm looking for budget options to accompany my fully burnt-in JVC HA-RX700 (owned for months now). I'm hard pressed looking for a worthy partner or even upgrades to these headphones. They sound absolutely great at the price I got them for. I believe they retail at about $60 or cheaper in the US nowadays, shipping included. I had them shipped here in the Philippines so I paid $100+ including international forwarding.
 

1. I'll be using the headphones mostly in the office or as an alternative gear when I listen at home.
2. I need some decent isolation and not so much leakage. I don't need to totally block out the world but I don't want to disturb those around me so much either. I know that the HD330s are semi-open but do they offer at least some decent isolation and significantly lesser leakage compared to fully open models? No question about the SRH440s in this department.
3. Soundstage is important to me. Coming from IEMs, I don't want to go back to that in-your-head sound presentation anymore. According to reviews, both of these headphones offer decent soundstage. Even the fully-closed SRH440s are praised for there decent soundstage. Some say that they even provide a decent amount of depth when amped. Which of the two, in your opinion, has a superior soundstage?
4. Natural sound is also important. Which of the two would you say sounds more natural?
5. I also lean towards a more bright, fun, and energetic listen. Which of the two, in your opinion, would be a more fun sounding headphone?
6. Build quality is also important. The Shure is more than 2x the price of the Superlux so I presume them to have much better build quality. I also like that they have a detachable cable and replaceable earpads. On the other hand, Superlux earpads are also compatible with Beyerdynamic earpads so that's a plus to the HD330s as well.
7. I need a good all-rounder as I mostly listen to multiple genres including 80s rock, progressive rock, new metal/rap core, symphonic metal (metal+classical fusion) jazz, jazz fusion, soul, pop, instrumentals and even some musical theater music at times.
8. I don't change/purchase headphones often so I need a long term companion which I will enjoy until they last and which could at least come close or compete with higher-end models. I'd like to avoid much diminishing returns in my investment. I believe these two are evenly matched as great investments.
9. Music source is Fiio X1 + E11k (A3) stacked. Will be playing mostly flac + a few MP3s at 320kpbs.

 
After much research, I've shortlisted these two as the best in my book, the Shure being more highly rated (it even made the Headroom Top 10 which says a lot). The Superlux has been compared with Beyerdynamics and some say they come close. That also says a lot.
 
In a nutshell, I'm looking for the delicate balance between, isolation, soundstage, and a fun-sounding all-rounder. I know closed-backs and open-backs are not usually matched up head to head around here as open-backs have some innate sonic advantages but I value your opinions. At both their prices, these two are great value headphones. It's only a matter of which one is best value for my needs.
 
P.S. - This is a re-post from the Help and Recommendations forum as it did not gain much traction in that forum. I'm hoping to get more responses in this forum if possible. 
 
Thanks in advance!