Hi Nick, It was not obvious to me either that good quality filament is a must with Ender 3 and also that the as-delivered very basic reel holder can cause feed problems. I have since been buying a better PLA plus filament and also PETG filament, and have very few build issues now. I also built a separate reel holder off the machine, with a centre axle holding ball bearings in printed hubs fitting the reels. A couple of shaft collars hold the reel on and keep the printed hubs engaged in the wheel. The reel holder was made of steel scrap and hangs from the floor joist above the machine, so it is completely isolated from machine vibration and feeds straight horizontally, from left side, into the Ender 3 extruder. It has improved things greatly and cost very little to make.
I also replaced the as-supplied build mat with a Creality glass bed plate – major improvement – and an all metal extruder. This extruder is better than the original but not optimal. Will be looking for a better extruder design on the next machine I buy.
All that said, I think my Ender 3 was excellent value for money and a great way to get started with 3D printing in the home shop. It has paid for itself many times over, by making usable assembly fixturing and press form tooling, working prototypes for linkages and mechanisms, and replacement parts for broken plastic bits (low stress indoor use parts). My two nieces have also had a ball with it making toys and action figures, movie characters, characters from books (most notably a family of 3 "Totori" characters from a popular book from Japan).