I’m not sure what the goal of your post is ?
Yes you can probably fine a cheaper PC.
But the OP wanted a Mac so thats the advice we were offering - which Mac to buy.
For other things, maybe, PC would be a good idea.
Specifically for Xojo, even a faster PC the IDE will work much slower than on a Mac. That is a fact.
Besides, that is a very tired argument. The OP has his reasons to want a Mac, just like you may have yours to want a PC.
for iOS dev, the mac is mandatory I’m afraid …
That is precisely what led to my first use of OSX many years ago. Then I discovered that I even liked Windows better when run in a virtual machine. Like OS/2, it was a “better Windows than Windows”. You so quickly get used to a multi-touch trackpad and gestures like two-finger scrolls etc that when I pulled out my actual Windows laptop, I could not believe how clumsy it felt.
Anyone have experience with MacBook 12" 1.2 with 8gb ram? (Maybe comparable with MacBook air) Ive had a 2013 MacBook air with 8gb and been very satisfied with performance of xojo, Photoshop etc
macbook air 1.3 2013 geekbench = 2500 (single core)
macbook 12" 1.2 2016 geekbench = 3000
so yes macbook may be faster.
Do you have a geekbench for the macbook 12" 2017 1.4 ghz, 16gb ?
thank you 
The only entry close to that which I found was a 1.2Gz model which got 3580 single core, and I could not tell how much memory it had. So presumably the 1.4GHz should be a little higher. It got 6815 in the multicore rating.
AppleInsider has a video which shows 3810 for the 1.2 model. You can pause the About This Mac screen in the video to see the exact configuration.
MacBook Air (13-inch Early 2015)
Single-Core Score Multi-Core Score
2981 5942
The computer has 8 GB of RAM.
Intel Core i5-5250U @ 1.60 GHz
1 processor, 2 cores, 4 threads
Because of the small display of a MacBook 12":
at the right side: I can click at “Inspector” to move the Inpsector out of the develop window, to see more of the app.
at the left side, there is the file browser view. Can I click on a button to hide this too, to get more space?
Does anyone of you have already bought the MB 12" 2017? Or try it in an Apple Store?
I’ve got one coming in a couple days with the 1.3 processor option. I won’t be using it for XOJO but I expect it to be at least twice as fast as my 2011 11" MacBook Air with its dying battery, which has served my needs well as a second Mac for taking minutes in meetings and giving presentations on.
Just got a 13" MacBook Pro with 16GB RAM, 512GB SSD and the i7 processor option. Considered the MacBook for a while. My reasons:
- I travel like crazy but the 13" Pro has basically the same weight as my current MacBook Air so there are no changes for me in that area
- Single core performance is still quite important for many of the apps I use.
- Multiple ports are a must for me. And Thunderbolt 3 gives me the ability to eventually plug it to a eGPU one day
Good review on Ars Technica:
https://arstechnica.com/apple/2017/06/mini-review-the-2017-macbook-comes-into-its-own/
any news to the topic: MacBook 12" 2017 and Xojo?
Why dont you put Xojo and a project on a Memory Stick and ask an Apple dealer (Apple Store) if you can make some tests on your own ?
If so, remember to send your feedback here
;-
Edit:
You: the people who want the answer.
geekbench would suggest it’s “fast enough”
https://browser.primatelabs.com/mac-benchmarks
I have a 2012 rMBP 2.7 Ghz which benchmarks at 3580
The 2017 MacBook m3 1.2 Ghz benchmarks at 3546
Dont see benchmarks for the i5 based one