Curious to know how you like the m16s compared to the jbl 530s, especially since the m 16s are on sale..
IMHO the M16 is better speaker. It is my favorite speaker under $1000 that I have owned or tried. The 530's are great speakers and are a fantastic deal at $300 or less on sale.
Both speakers require subs in order to truly flesh out the bass(and it is required at high SPL) in a farfield set-up in a medium or bigger room.
Both speakers can handle about the same level of SPL with the 530 maybe digging a tiny bit deeper but unable to play quite as loud on bass heavy tracks. The M16 does sound a bit more powerful but the 530 does well for a small driver.
My room is 23x12x8.5'tall and I do louder sessions regularly and again I recommend a subwoofer or two or three. In a typical set-up I'd high pass the 530's between 80-100hrz and the M16 at 70-90. In my set-up I actually high pass the 530's at 125hrz in a situation where that makes sense. High passed like that the 530's can play very loud without any issue and very low distortion as long as you have power as they are very power-hungry.
Again, neither the M16 nor 530 can do super loud in my room with bass inclusive or bass heavy material without high passing. You will overdrive the bass units. I believe ultimately the 530's tweeter can actually handle higher SPL than the M16 without strain although the M16 is no slouch and for an inexpensive looking tweeter is quite impressive.
I love the 530's and think they have a very special sound and for the money are a great value. $600 or under I have yet to really like another speaker more.
That said and everything positive I have said about the 530, the M16 is somehow just a better sounding speaker. It really sounds even better. It is more money and that is going to boil down to your resources. You have to pay more to get more and for a lot of reasons this does make sense. Paying 2-3 times as much for a bit of an upgrade in sound can seem hard to justify for some and for others it is a no brainer. If money is tight I'd say stick with the 530's, if you are really curious and a few hundred bucks is just money well spent enjoying your audio hobby then I do think the M16 are worth buying and a small but meaningful upgrade.
As an aside to the 530 vs M16.
I preferred the M16 to the KEF R3 as an example of how good they may be depending on your tastes. I liked the M16 so much that I decided to trust the engineers and splurge on the M126be. I am not financially wealthy and was ready to return them at the slightest whiff of them not being worth $$$$$. No issues and I am deff keeping them. They sound amazing and in the way of the best speakers the real proof of gains in SG and enjoyment is not shock value but rather when you go back to the sets you upgraded from and realize it really is a downgrade to back.
Is the M126be worth that much more than the 530? No, of course not in a $ vs performance only comparison as the 530's are really nice for $250-600. However when not looking at just costs the M126be is absolutely significantly better IMHO. So if that is what absolutely significantly better than already really good costs then so be it. I have no regrets. They honestly made the R3 and even the M16's sound like definite tiers down. It was not a hard call.