I've only seen my own teckels working, so can only speak for my own.
I have had a couple of good terriers and seen some good terriers working.
I hunt with a very good pack of hounds.
I have one teckel that can be hard enough on a fox. But the others either aren't interested in travelling or will go up and sound away for 15 or 20.minutes. you'll get foxes at a handy depth with them but I wouldn't be digging 6 foot to them. It suits me as I want them hunting. If you are serious about digging from what i have seen of my own teckels, a terrier from proper working lines would be a far better choice. But as you know even the best of lines throw duds.
As I said I hunt with a very good pack of hounds. Again judging by my teckels hounds do a better job if you have the country to hunt and the space to kennel them
But for what I want my teckels suit me perfectly. Hunting heavy ditches and small covers. They are small and easy to kennel, which is a big plus for me. They are pleasant dogs to have around the place and make good pets.
As I always say about mine, they're no world beaters but I knock a bit of craic out of them. And as I'm the one feeding them and picking up their **** once they keep me happy that's all that matters.
Please dont let this get into which breed is better, that wasnt the purpose. Just keen to learn more about this fascinating breed.
Thanks again for the replies.