If you are needing to bottle thousands of bottles in a run with just a few products, a pressurized unit may work for you and pay for itself over time.
Gravity units won't work well with paste type products. Fluid type products may work well once you get it calibrated well.
Some bottling units say you can use high viscosity product in them however, they will usually require some heating / warming to keep the material flowable and workable thru the unit. There is warm up time needed to begin your bottling.
I have looked into several options over the years. When you consider their cost it may not seem like such a good idea. Then hopefully it will do what you want it to do.
Keep in mind when you switch to another product using a bottling unit, you will need to clean everything well. This is needed to prevent cross odor product contamination if you only have one designated unit to use.
We use spring release scoops for most of our bottling. They are available in "various sizes" and work well once you get on to their use. Easy to clean and minimum waste.
These scoops do most of our work for our bottling gal. I still bottle some, however our gal keeps us in good inventory. She can move along very efficiently and weigh each container to ensure accurate volume, particluarly on the larger volume containers.
Filling 8oz, 16oz and gallon bottles by how they look by "using your eye" to determine volume can fool you. It can settle over weeks sitting on the shelf.
Scale weight ensures accuracy and consistent volume. Some may not use our detail in bottling but that is how we operate.
When you check them at a later date they may have settled in volume. Tapping each jar firmly during your bottling process will help ensure a good job.
I am not sold on automation for heavy paste like baits and lures. If you get an air pocket in your "hopper fill" it can give you inconsistent volume results.