"Should I upgrade" questions are always tough. For me, aesthetic improvements get a free pass as an automatic yes.
I look for something being 50%+ better before upgrading from something that's perfectly serviceable. My M5HP is probably 20% better than the Kanto Yumi it replaced, and with major EQ tweaks it would be closer to zero. I kept them anyway because of aesthetics. My Harman curve-hugging Sony WF1000XM3 wireless earbuds were 100% better than my Apple EarPods with Dirac Realplayer HD, themselves the best headphones I had owned up to that point.
On the other hand, some things just aren't worth it. I test drove a Tesla Model S P85 when it came out, and my first impression was "This drives like a Lexus ES with triple the horsepower and one pedal driving."
Sometimes you won't know if it's worth it until you try it. I did all the low hanging fruit like air sealing, so I recently upgraded the attic insulation of my older home from R20 to R50 and fixed the ventilation. OMG, I cut my space heating in half and the payback period of the install appears to be 5 years. I'm now within spitting distance of EnerPHit standards. My heat loss is 9,000-12,000 BTU/hr during the 50 heat degree days that we can get in Edmonton. That's like heating a home with 2 hair dryers (a PassivHaus-certified home only needs 5000 BTU/hr). We'll see what my A/C usage is like this summer, but a 66% reduction in run time looks achievable, because a heat soaked attic is apparently a thing. | 
