In addition to an inexpensive grinder (Carlton), I have quite a few different types of file guides. It is easy to collect interesting jigs and guides, not all of them get used frequently.
I like the Carlton File-O-Plate best, keeps the file at the proper height to the tooth and allows me to adjust the angle if I want to. I like the progressive depth gauge on the File-O-Plate as well. The biggest drawback to the File-O-Plate in my opinion is it does tend to dull a file much more quickly since you are constantly in contact with the stainless steel plate. Except for this issue, the File-O-Plate would be my #1 guide for sharpening all chains. I have a pretty complete inventory of sizes and types so I can handle most chains that come along with the exception of those over .404 pitch.
I also have the Husqvarna guides and while I have used them, I find they to not fit a wide variety of chain types and in the process of collecting saws and such, I have a lot of different chains as well. I do not find the Husky depth gauge to be a easy to use as the Carlton.
In the past 12 months or so I have picked up several of the roller type guides sold as "Windsor" brand. I really like the feel of these, and I like the guides better than the Husky type. Like the Husky, they don't fit all types of chain. To be honest I don't even remember if the Windsor guide has a depth gauge of any sort.
I also have a couple of the Oregon and one Granberg for bar mounted guides. I have used the Oregon to try and make a more aggressive chain for "racing" but have to agree that is it not a particularly solid device. The Granberg is a vintage model still in the package, I don't know if I will take it out and use it, or just keep in in the box.
I also have three different types of file mounted guides:
One is a "V" shaped guide that does work very nicely on the large pitch chains (1/2, 9/16, and 5/8" pitch) but the small diameter files in the .325 guide seem to flex.
I also have several of the ones Rockcrusher sold on e-bay with a simple round rod with the file attached. I like the way it helps me to hold the proper depth with filing the teeth, but provides complete flexibility on the angles. If I only had one guide to choose from, this would be my choice since it can work with virtually any chain size or type.
Lastly, I have several of the flat type guides that the file attaches to and ride on the cutters to control the depth when filing. I like these the least and only use one if there is no other tool to help me.
I have filed a few chains free hand, but find that I need a guide every so often or I tend to get the file too low in the tooth, cuts quickly for a bit but does not hole the edge very long.
For depth gauges (rakers, drags, etc.) I like the Herr tool and have them in 0.030. 0.035, and 0.040". I have a couple of others in 0.020 and 0.025" but prefer the Herr for most of my needs. Keep in mind that I do sharpen a number of large pitch chains for the old gear drive saws so 0.035 and 0.040 are not excessive for regular use.
I have not tried the "all in one" type tools from Pferd or Stihl, perhaps one day when somebody lets me try one I will add yet another tool to the box of chain sharpening options.
All this to say to the OP: Your shop has really let you down regarding chain sharpening options. I have been in a number of places where they will not adjust the depth gauges when the sharpen chains; if they don't understand chain sharpening any better than that, well it would be best to use some other option.
Mark