I want help, longe distance or better overall performance?

Hello
Today I shoot with a 6D and I'm impressed of it's iso handling. Soon the spring will appear and all the insects will arrive. So now I need a macro lens.
Earlier I've owned the old Tamron 90 and Sigma 105 OS. Now I own nothing. So, I can get two lenses for all most the same money in used condition from a shop. With 3 month guarantee.

I feel that I need almost 100 mm for macro shooting with my full fram body so now I want some thougths from you. The Canon 100 has very good reviews on the net but the Sigma has 50 mm more and tripod collar. I know that the Canon 100 mm can use tripod collar but all the comments about having tripod collar on it has been strange, it's expensive and it's hard to get it work, I don't know?. If I can get a good answear if I can use tripod collar with the Canon 100 mm it will help me to decide I think.

The prices of the these lenses are:
Canon EF 100/2.8 USM Macro : 350 USD (Good condition with box, has a little damage to the lens frame where the filter will sit. Do not know if a filter can be used)
Sigma 150/2.8 Macro (Non OS): 390 USD (Mint conditon, complete with everything)

One thing that I'm worry about when it comes to the Sigma, it's the vignetting on a ff body. Even att f8 it has 0,5 ev vignetting.
I don't know about this, I want some help!

Okay, you mean the 150 OS, not 105 OS.

Personally, I would prefer the newer version of 100mm (L with IS). Whereas for 150mm, I can live without the OS as it's on a tripod most of the times.

It is the 150 (Non OS) I'm talking about. What do you think about the 150 macro lens? Good? The weight? Optical performace etc...

Since using the 6D (instead of the 7D) I have been using the 180L more for butterflies and dragonflies simply because you need to be ~40% closer for the same framing.

However I also have the option of the 100 USM and MP-E for less flighty subjects.