Is it now with APFS better time for booting system from external SSD?

[Darajavahus]

I have late 2012 21.5 iMac with scandalous 5400-rpm HDD (which 5 years later the newest 21.5 iMacs still have...) Since the beginning, I was thinking about getting external SSD, and now with APFS, it seems like best time to finally get to it. Instead of upgrading system I leave it in case as it is on the HDD and when High Sierra comes out I do a clean install on USB 3.0 SSD. Or am I missing something and that is a bad idea?

With USB 3.0 SSD will I get all the benefits of APFS, or is there something with APFS that would make booting from the external SSD not recommended?

Also, any recommendations for enclosures or adapters to connect the SSD externally to USB 3.0? Is UASP something that matters? No thunderbolt, I wanna get this done cheapest way, not sure how much longer I will have to keep this old iMac, hopefully next year iMacs will be all flash. (sorry for my poor English)

 

[dianeoforegon]

I fear that the iMac will continue as Fusion unless you select to get SSD instead.

I have an SSD in an enclosure and am very happy with the speed even when booting from the external. I selected to de-fuse my Fusion iMac and have the small 128GB SSD drive with APFS. I use the 1TB drive for all my data like documents, movies, music and pictures. Only Desktop, download and User's Library are using internal drive.

You could install High Sierra on the external drive then point back to your internal drive for documents, movies, music and pictures.

 

[Fishrrman]

I think you'd do fine setting up an external boot SSD with High Sierra.

There are several brands of USB3 SSD's ready-to-go out there.

Sandisk, Samsung (t3 or t5), etc.