I have a Dell Optiplex 9020 from 2014. Before that I had the same computers as @Peter. Always put together generically. Which I miss very much. Apart from being cheaper I got the best of any parts that were available.
The Dell - touch wood - is not too bad. I did upgrade it at end of 2016 to 16 GB RAM (from 8 GB), but to be honest, don't feel it's that much faster.
I also have a Toshiba Ultrabook Portege - very light - laptop from 2012 - still in good condition. I use it only for traveling. It's faster than the Dell. For some or other reason.
Both devices have i7 Pentium. I'm still working with Windows 7 on them. Probably have to think of changing soon, and decided to wait until it is really necessary. I.e. software forces me to change. For now I have OEM software on it that will cost a lot of money to replace. Such as Microsoft Office that I purchased for 1$ in 2016 when I was still working in the UAE.