Choosing the right filament brand is difficult with all the different manufacturers out there to pick from. Many filaments out there won't properly extrude and you end up with low quality prints. This usually happens with cheap China made filament, where quality control is lacking. The higher tolerances in diameter and roundness causes issues due to the inconsistent size and amount of material being extruded. If the filament is too thick in areas, the nozzle may jam. When the filament diameter is too thin, the gears in the extruder may lose grip, causing little to no filament to come out of the nozzle.
Another common issue to be aware of in cheaper filament is the presence of voids. If not careful, during the manufacturing process, tiny bubbles create these pockets of air within the filament. These cavities will reduce the quality of the print by leaving voids in the surface. Loud popping sounds when printing is a good indication of these air bubbles as well. This is caused by the rapid expansion of the air and moisture pushing out through the heated nozzle.
Sub-par raw materials and foreign additives are used in cheap filaments to keep the manufacturer's costs low. The problem with starting off with bad raw materials is that you end up with a questionable product. Prints will fail, hours will be lost, and you may even need to replace a nozzle or extruder. Many China manufacturers add calcium carbonate as a filler material for example, which causes the filament to be very brittle. This will make it difficult to even feed the filament into the 3D printer.
Getting quality filament doesn't mean you need to go buy the most expensive filament available. Many expensive filaments are priced high because you are paying for the brand name and not necessarily a better product. Mitus brand filament however, is very competitively priced with even the cheap China filament. But unlike the cheap filament, Mitus is made in America, and the quality control is top notch. Four laser micrometers along the production line keep the tolerances tight, and only quality raw materials and colorants are used. There are no fillers, no regrind, or recycled materials used. Mitus prints smoothly each and every time, your satisfaction is guaranteed.