Timberline sharpener test drive?

I can't answer your question as far as satisfaction guaranteed, but their are many satisfied users on this site. I own one myself, but have very limited time using it, so I can't say I love it yet.

After using most every other jig/method and freehand file over 40 + years of wood cutting I must say that I have been impressed with the timberline; it has become my method of choice.....

Not sure about the trial period thing, but I found the timberline folks to be very responsive when I contacted them. The sharpener is awesome in my opinion. I've been using it for a few years and have not had to have any chains sharpened professionally in that time. Plus, my chains are way sharper than I could get them by other methods--even when the pro sharpened them. I find that my chains are lasting longer too. It isn't cheap, but in my opinion, the only risk is making your chainsaw guy think you are going to another shop. Seriously, this happened to me--the local Stihl dealer asked me if he did something to take my business elsewhere. I told him about the timberline, so we're OK now.

I haven't used my Timberline since I got a bench grinder. We can prolly work something out.

I have a timberline, the claims of sharper and lasting longer than a machine sharpening are true. I still use a grinder for a rocked chain. What surprised me most is how little material is actually removed by the timberline, doubt you would be disappointed.

I love mine. Have had it a couple of years. I've used a file, grinder, and the timberline. The timberline is my favorite. As others have said, it takes tiny amounts of material off, compared to a grinder (in my experience anyway). Also, it doesn't need electricity (I sharpen in the woods usually).

I use mine more than my bench grinder. As above the bench grinder is saved for severe duty...or other people's chains.