I'm anxiously awaiting this 24-70 release. Through a combination of renting and owning I've tested the EF 24-70 f4, EF 24-70 f2.8, and the RF 24-105 f4 - all on my EOS RP. I found the two f4 lenses to have equal sharpness, but the 2.8 was better than both. And, I was surprised to find I did not miss the IS. I can get an excellent condition used EF 2.8 for about $1300. I know the RF will have IS, but it will probably be heavier and maybe even larger than the EF+adapter. So, to get me to spring for the extra $1K for the RF, it first has to be not huge, and the IQ has to be even better than the EF version. If not, I'll get the EF and put the difference toward the RF 70-200. Looking forward to the release.
My plan is to rent the RF24-105, RF24-70, RF24-240 and EF70-200 F4 II for a week and see which I like best. I hope it's the 24-240, unless I win a lottery
The rental place is close enough and affordable enough that I am almost completely over my GAS for the f/1.2 primes.