There was a period where the qc on Case knives was less than great. However, if you get back into the knives that have the Case XX tang stamp or even the earlier Tested versions, the quality is usually very good. I would say that some are even on par with some of the custom knives. I'm a little biased though..

These earlier Case knives have a very big following and command a bigger price, but IMHO they are well worth it... Do a little searching on the big auction site and you will find quite a few of them.
As I mentioned, I can't give you an honest opinion on current production knives, but a lot of folks here have been very happy with the quality of them.
Another thing you may want to check out is the earlier Scharde Walden knives.
Very well made, and they did an incredible job with their 1095 blades.
They can be had for less money than the early Case knives, but there is absolutely nothing wrong with the quality. There were some that were made with bone scales, but those aren't very common and command a much higher price. Scharde went out of business in 2004, but there are still knives being made overseas with the Schrade name. Make sure you get one that is U.S made, because the current imported knives are nothing like the originals.
I have a few and they have jigged Delrin scales. I'm not usually a big fan of Delrin, but I really like these knives. It would give you a great way to get into slipjoints without spending a lot of money, until you get a feel for what you really like.