I like gels, no study, just like them, they stay on top of the carpet and don't run down into the pad, benefits are; no de-laminated carpet backing and product stays on the stain where it can work longer and better.
Gels do a POOR job of penetrating the fiber bundle to remove stains. They were only formulated to eliminate delamination from slow-evaporating citrus solvents. Use a well-formulated liquid POG that evaporates fast enough to minimize damage to the backing. You will be done quicker as well. Larry
We find the liquid solvents to work faster and better like Larry said. We do use gels too on other types like thick glue ,caulk and tar spots.
I use Gels primarily. After they took away my Tri-111 solvents and switched to the "safer" stuff I moved t the citrus based gels and they work fine. They just require more time. Aaron
I agree with most of the posts above. Gels are safer. They also will stay on a heavy spot longer and keep working when some liquids may have evaporated. Liquid solvents usually work faster, but sometimes evaporate too fast to have finished the job. Definitely a place for both in the spotting kit. Scott Warrington
I use Master Gel for all my residential jobs and invade(liquid) for commercial grade carpet. Master Gel all the way!
