But what I need to know is if everything I do will be easier, faster, and more fun.
You'll probably kill me for asking this, but if the old Pi 3 B was 1.2GHz and the new one is 1.4GHz does that mean I can print 16.666666% faster?
No. The limit on your printing speed is most likely in your printer, not in how fast OctoPrint can send the next command to your printer.
What it might do is let your Raspberry Pi do more other things while it is controlling your printer.
I received my pi 3b+ 2 days ago and loaded the lastest image available then, I didnt even know it was just released ., everything seems to be working so far .
As a small update on this:
WiFi country isn't set by default, making headless bootstrapping tricky. Workaround has been added to OctoPi and should be in the current nightly, but so far no way to test this.
And another update on this:
Current nightly builds (since 2018-03-15) should at least in theory now support the RPi 3+, if everything works as it should however has yet to be determined.
I'm running Webmin on my RP3, running Octoprint. I watch the CPU utilization when doing various things in the system. For example, when I upload gcode, I watch the CPU spike to around 75% while it's assessing metrics for print-time and cost analysis.
When it's printing, I don't see the CPU spiking more than 12%-15%. So, that leads me to believe that the current model should be MORE than sufficient to carry out your regular printing tasks; along with some other things, if you so chose.
This is also while I have Printoid (Android) running on my phone, connected to Octoprint. AND running the webcam stream in my desktop browser.
It should be good...
I don't see this as any benefit to octopi, but it should make my Kodi box happier!
My mistake , it is just the ordinary 3B that they sent , FALSE ALARM 
this morning i have running the octoprint nightly 0.15,and it works now
0.14 will not working for me.
but if i press print knob in octoprint,then the print is blue en still blue,en not the cancel or pause.
sorry my english is not good 
I was semi-stupid and got the 3 b+ and now the link for nightly builds does not work atm.. http://gnethomelinux.com/OctoPi/nightly/
gives me: ERR_CONNECTION_TIMED_OUT
Probably due to this
Until the page comes back up, this image at least was reported to work on this OctoPi ticket.
Hello guys, I got an RPI B+ and installed the Nightly Builds "2018-03-23_2018-03-13-octopi-stretch-lite-0.15.0.zip" on that...
But, on the download page I see the new version: 2018-03-26_2018-03-13-octopi-stretch-lite-0.15.0.zip, so the question is, how I get the update from my version 2018-03-23 with the new relese 2018-03-26..???
I need reinstall all things or the sistem is able to update it...?
Thx for your help...
Hi, I have just found Octopi and have tried loading it on to a Pi 3+, however no joy.
After creating an SD card with 0.14 and powering it up it appears to have a problem as the red LED flashes a pattern. I haven't had time to attach a screen yet, but intend to do so tomorrow. If wanted I will supply the screen messages.
David
@Macca45 I suggest you read the article again which clearly states that OctoPi 0.14 won't work with the Pi 3+ 
Yes I had just found that where you said you did not expect it to work. I was merely confirming that it doesn't work.
Ah, ok then. It sounded more like "why isn't it working" - and you wouldn't believe how many people already actually didn't read the article and then opened up support requests, hence my assumption this was the case here as well.
For image updates you usually need to reinstall. If it's just a new base image, the usual ways of updating a Raspbian image incl the kernel might be enough though.
So I just got a 3+ and trying to print with octopi/octoprint. I don't think the latest stable one works... I got the image in via both etcher and windisk imager and when I put the card in, I get a flashing red light and rainbow screen... Going to try a nightly now 