Hi Mark,
I haven't used HitFilm or even heard of it but i'm not the creative kind anymore.
I have used iMacs since 2006 with the first Intel model. I used iPhoto, Aperture, iMovie, Final Cut and so on to make short episodes about my friends and I Mountain Biking. I made 300+ ,learning as i went.
I too now have a 2017 21.5" 4K iMac with a Intel Quad Core i5 - 3.0 GHz - 16 GB RAM - 1TB SSD which i bought on Gumtree for £130! LOT of 2017 models on the site now. From £100 with no details to £400 with a lot of details.That's a bit much i think...........
I don't do anything on it really as it's an upgrade from one of many 2011 iMacs i have (and still do) owned, repaired and sold. Really 2006-2011 models due to not loving Apples obsession about a "5mm at the edge" computer. I wasn't loving the inside of them or the cost.
I lost everything in a fire. Every photo i ever took. All Videos i made on dvds that at first took so long to edit and transfer. There were stacks of 50 and 100 discs in the room, Photos including my 7x5 inch physical picture from 35mm cameras. Every one of my 11,000 photographs that i scanned in to my 06' iMac using a £400 scanner that i bought new and sold three weeks later for £325. Epson i think. I just went for the best at the time. But computers, old internal drives, external ones, all my cameras and camcorders and all the cards and tapes. And my Volvo 850R Turbo Estate in lime green that took 8 years to build, carried 6 bikes at 154mph. It's only stuff right?
I use Final Cut Pro, motion, Compressor and a whole host of the latest and newest Applications that the App Store advertises and it'll appear on this machine like magic. I don't use them. It just looks good.
I think i tried to install High Sierra when i got this 2017 model to then update it with anything i had on it but it wouldn't work even though HS can use APFS. Reading the communities it's the fact that it has newer Hardware and software and it isn't built for the past which is just perfect for me as i have none. I have two 2011 iMacs right here with 1TB Crucial SSDs and 32GB of Crucial RAM as Its the best iMac in my opinion plus i have a 'few' mountain biking dvds from the good ole days. 2004-2018. Events are crap but some of the films being made are cracking.
If you take one thing from this, in fact take two things the second being this is the most effort I've shown for 6 years or so on anything. The first is NO! Nobody can refurbish an Apple product.
When i repaired, replaced parts or put together iPhones and iMacs they sold as they were, used but opened, cleaned, tested, replaced with improved parts etc.
On eBay you can class a iMac as Refurbished is you give the casing and screen a wipe with a moist cloth. I'm not kidding, i had this massive argument about it as i needed parts and i bought iMacs which over the years and it became clear that people were not opening them up to install a new hard drive or add RAM because eBay got lazy and refurbished meant less and less just like their quality control of the listings, the actual goods, their location. 20 year on eBay, 7000+ all positive FB. Ended up being a big seller of Original cinema posters for the UK, Europe, Australia, US. Anywhere there was a cool poster or a warehouse full of them. Lot of money but then market crash and posters weren't as wanted as before.
Well that's me set for the long day ahead..............:(