The EOS M lineup will be addressed later in 2020 [CR1]

[SteveC]

15-45mm?

At least some reviewers (who have access to both this and the older 18-55) claim that was a significant step down.

 

[jolyonralph]

15-45mm?

No, the 18-55 is a better lens optically - I own both lenses.

 

[Rocky]

I own two 18-55 and the 15-45. Optically, they are about the same. However, the 18-55 is mostly metal on the outside, including the lens mount. The 15-45 is all plastic outside, including the lens mount. Definitely the 15-45 is a step down from 18-55 in construction. If you are shooting city scape and land scape, the 15-45 is more suitable than the 18-55.

 

[andrei1989]

i also own the 15-45 and the 18-55...what i don't like most about the 15-45 is the collapsible design. i feel i'm missing moments having to extend the lens and i don't trust it (and me) to leave it open all the time. what i don't like about the 18-55 is that it starts at 18 )
i have the ef-s 15-85 as well which solves both complaints but it is a beast on the M5 with the adapter
i also dipped my toes into the fuji system and their 16-50 kit lens is really good...and they have the mirrorless equivalent of the ef-s 15-85 i've been asking for from canon: 16-80 f4, which i'm more and more tempted to buy...

 

[Rocky]

i also own the 15-45 and the 18-55...what i don't like most about the 15-45 is the collapsible design. i feel i'm missing moments having to extend the lens and i don't trust it (and me) to leave it open all the time. what i don't like about the 18-55 is that it starts at 18 )
i have the ef-s 15-85 as well which solves both complaints but it is a beast on the M5 with the adapter
i also dipped my toes into the fuji system and their 16-50 kit lens is really good...and they have the mirrorless equivalent of the ef-s 15-85 i've been asking for from canon: 16-80 f4, which i'm more and more tempted to buy...

I have been using the 15-45 ( along with other lenses) on my M5 for over 2 years and do a lot of "shoot and run". The only time I collapse the lens is when I need to put it back in the the camera case. So far so good. Even regular zoom lenses changes length when you zoom. No body that I know is concerned about it.