Thought I’d chuck my 2 cents worth in as well.
I don’t encounter E Torx that often, but when I do they seem to be used on higher torque or limited space applications, sometimes both.
For that reason, I prefer to use sockets of reasonable quality. Don’t have to be Snap On, but say in the “top half” of the quality spectrum.
With regard to Snap On, they don’t load the prices of their more specialised tools, so I would never disregard them for this sort if thing, but I note that the O.P. is looking for something at a lower price level.
For me, admittedly on the other side of the pond, I’d be looking at Hazet, Stahlwille, KoKen and Facom.
In the U.S. the Hazet are going to be costly, perhaps comparable to Snap On, but of no better quality so probably not my first choice.
They are nice though, and tough.
I have E Torx by Stahlwille, and they have been great. Part of the reason I got Stahlwille was the trade discount at the time. Totally happy with them, but if I was replacing them I’d probsbly go KoKen or Facom.
The KoKen are superb in every respect, and reasonably priced too. They also offer just about every option you could want. Far more than other manufacturers.
KoKen have pretty much become my default option for any specialised socket now.

.
Facom are also nice. I find them generally quite strong, the finish is good, and the price (at least for me) is about the most competitive.
If the O.P. needs E20 then that’s going to be 1/2” drive and the euro manufacturers traditionally offer a good selection of 1/2“ drive tools.
A couple of other considerations -
Some folks have mentioned the different chamfer on some tools. There is actually a “low profile“ E torx. I have not encountered these (seems to be mostly on Japanese products) but if you need it, some manufacturers offer separate tools for the purpose. Here KoKen.
Some manufacturers offer generic “star” sockets. They might be o.k, and those companies may be passing on the savings they make by not paying a license, but… you never know?
When Pozidriv screws were introduced, the licensing process for the screwdrivers included not only the shape of the tip, but the steel grade and heat treatment. (You will sometimes see otherwise identical Phillips and Pozidriv screwdrivers with blades from different steel).
I don’t know if this is the case with things like E Torx, but I do know that a tool using the Torx name will probably be up to spec, anything else is unknown.
Finally, I find I need a different spread of E Torx tools, compared to regular hex. With regular hex I can do 90% of what I need with regular sockets, but I need all the sizes.
With E Torx I find I only need a few sizes (somebody mentioned E10 and E12 on BMW’s - yes absolutely agreed) but I have needed all the options in these sizes - regular socket, deep and universal.
You might think that things like deep E Torx sockets are too specialised, but so often E Torx are used where access is tight, and I’ve needed the deep socket simply because it was able to access a fastener tight against a component where a regular length would not fit.
Once again, KoKen are a good choice as they offer all these options.
