I've used this one in almost all of my vintage PC's.

https://www.amazon.com/StarTech-com-Single-Adapter-Reader-35BAYCF2IDE/dp/B000T9QQP0

Things I like about it are:

1. Front Loading. Makes it easy to take out and then use a CF reader on a PC to transfer files.
2. It has a master/slave switch. Many adapters do not.
   
3. Easy to install where a floppy might go, or easy to find a 3.5" to 5.25" adapter to mount it.
   

My biggest complaint is that it only comes in black. I wish it came in a light color that matched older systems better.