Photography is a hobby for me to ENJOY. So I weigh my purchases with this question in mind: Will this piece of gear enhance my pleasure from my hobby?6D hardly a 'heavier' camera plus the 100L looks beautiful on a 6D : }
For for example, when I asked myself if I should upgrade from the 550d to the 6d - the answer was NO. For what I do - having a FF heavier camera will not make any substantial contribution to my hobby.
On the other hand I purchased a 100L - and enjoy it immensely.
I know don't think I'm immune to GAS (Gear Acquisition Syndrome) - But I'm on a budget and need to spend carefully.
It's good to be careful, because once you take the full-frame 'leap', all hope for control of GAS is lost.
5D3, 5D2, Sony α6000, G16 | EF: SY14/2.8, V20/3.5, 28/2.8 IS, Ʃ35/1.4, 50/1.8, 50/1.8 STM, Ʃ50/1.4 EX, 100/2.8L IS Macro, 16-35/4L IS, 24-105/4L IS, 70-200/2.8L IS II, 1.4x II, 2.0x III, T28-300 VC PZD, 70-300L IS, Ʃ150-600 OS HSM S | E: SY12/2, 35/1.8 OSS, 16-70 ZA OSS, 55-210 OSS, SY300/6.3 ED UMC