M5 owners, (and 18-150 ones) please chime in.

1. I always thought the M3 overexposed a bit, the M5 in my taste seems to get it right. So you're not crazy here rather you're very observant which is good, but, it may be a personal preference to my point. My former 5DIII and now M5 had/have about the same exposure, which I like. I didn't like the M3 or G1X II (both DIGIC6)'s exposure defaults which were about 1/3 to 2/3 stops too high. I got used to the M3 / G1X II, but going back to the 1/3 to 2/3 less of the M5 is much happier for me. A very gifted counterpart of mine that shoots on a 5DII normally shots either default or +2/3 stops on his 5DII, and I've never complained when he did my wedding, but I noted he loved Av f/8 and +2/3 stops on like half my wedding. Sure. Worked out great, even though I normally leave my exp comp alone when I can as a purist.

2. Yup, same problem. I just flip my camera off and then on, a lot. I got used to doing that on my former M3, just it's a lot easier on the M5 with it's switch vs the button of the M3.

3. I don't adapt a lot of glass, but others have had that complaint. No suggestions as my primary adaption is the EF 50 f/1.8 STM which doesn't have IS.

4. The EF-M 18-150 IS STM is excellent, for what it is. If you've ever used a superzoom lens before, say the EF-S 18-200 or EF-S 18-135, any of em, you know there is some compromises made optically, true. The EF-M 18-150 IS STM performs VERY well for a superzoom, but, yes, it still makes some trade-offs. I still have my 18-150, still haven't gotten around to selling it (too lazy/busy/hate eBay and CL anyways) and this weekend I shot my EF-M 55-200 IS STM and 28 Macro with excellent results at the beach. Ironically never touched my 11-22 in the bag. I also used my 18-150 though on an evening walk where I didn't want my bag along, also did well, for what it was, but yes, my 11-22 + 55-200 obviously destroy it (optically) combined, no offense to the 18-150.

My advice, give the M5 some time on the exp comp, and don't be afraid to run it hot like my counterpart runs his 5DII half the time; personal preference here.

Turning the camera off, does wonders for the battery, and wake-up time is about the same time as turning it on anyways. You get used to it once you make on/off a habit, once you do that is, in the meantime, yes, drive you crazy during the adaption period.

18-150? I want to sell mine, but it still gets enough use during lazy moments I keep it. Optically the 55-200 and 11-22 perform better and give more interesting shots at 200mm and 11mm extremes respectively too. Personal preference again. The 18-150 has better IS, and faster AF then the 55-200, but, the 55-200 is sharper in the center, and does 200mm. Also the 18-150 does video IS combo, wheras my 55-200 and 11-22 don't. At the end of the day, those minor pluses of the 18-150 are still outweighed by the benefits of more extreme focals of a 11-22 / 55-200 combo, and better optics, you just get better pictures from other lenses, but, you have to do a lens swap, which the 18-150 "cures", and is less bad (probably the best I've shot actually) then other superzooms out there, but it's still a superzoom. I'm not a superzoom person either, but, I'm lazy at times too, and it fits the lazy bill quite nicely.