Lens for streetlife Canon 24-105 STM vs Canon 24-70/4L vs Tamron 24-70/2.8VC

First of all, I have to say thanks to all you guys who have helped me a lot. All my questions has been responsed rightfully with details even beyond my expectation. However, it is a shame on me that yet I can not decide. I have been a bad decision taker since I was a child.

For the zoom lens battle for street use, there has been a big turn today when I ran to a local store for reality check. Tamron 24-70 is definitely OFF the list due to its heaviness. Also, it is too noticeable being hand-held on streets. I have not checked further but for me it is enough. Another surprise (to me) is that Canon 24-105L has made its COMEBACK to the shortlist. The corner performance is much better on real life photos than on those Internet testing charts. For IQ I thought I have no further demand. F4 and IS both are amazing. However, I prefer the lens to be a little bit more compact so it is not much revealing on streets. So from now on, it will be my final decision between 24-70/4L and 24-105L.

And MohammedB is absolutely right! Another scenario I have plotted at first place is buying more primes. I have a “prime shooting mind” so I firstly thought about it. My (planned) street gear would be: Canon 35IS + 50/1.8II (which I already own, and love- no need upgrade) + Canon 85/1.8. Someone might say that the total weight will surpass a zoom lens. But for me, the matter is all about the weight on my neck, not about the weight in my back pack. The main problem with this solution is that I may miss some critical moments on street due to delay time to change lenses. This question maybe I am the only one who can answer for myself. However, if anyone has experience shooting three primes outdoor and changing lenses during critical moment, please tell me.

Last solution I have slightly thought about is a mirrorless camera, e.g. Fujifilm X-E1 + 18-55mm XF. Big advantage is the compactness, and also style. The disadvantage is DOF loss due to crop sensor. Following the same route, I also think of EOS M system, which may utilize the EF lenses I have got. But the street photos I found on Flickr taken by EOS M is too “point and shoot” quality imho.