I've only been loading for a little more than 10 years, so in comparison with some of you I'm still new at the game (and freely admit it). I also only load for a few calibers (9mm - .45 ACP - .38 SPL - .30-06 - and soon .243 WIN). But I have to say that, as with others, my experience with Lee produces has been very positive.
I started reloading with a 2nd hand Lee Pro 1000 press I got for $50 that was set up for .45 ACP. I added a set of 9mm dies and the small pistol shell plate carrier soon after, and have probably loaded 15,000 rounds of 9mm and .45 ACP combined. I don't load nearly as much .38 SPL, so it hardly counts, and my .30-06 I load on a single-stage RCBS Rock Chucker.
I have had the occasional glitch with the Pro 1000, sure. Generally, the problems were self induced during a switch from one caliber to another (although I had a nightmarish primer feed problem I caused once... but that's a different story).
I compare my experience with the Lee Pro 1000 to a couple of my friends that have Dillon presses, and have to say that I'm not at all displeased with the comparison. The Dillon presses can be difficult to set up and tweak, and are occasionally finicky - much like my Lee. Once they are set up, they tend to run well - much like my Lee. Sure, on a Dillon with all the bells and whistles you can crank out a good many more shells in less time than I can with my Lee, but I've never needed to do that level of production. Besides, I spent about one tenth the money...
As to the dies, all my dies are Lee, and I couldn't be happier. I started with Lee dies for the .45 and 9mm, and borrowed RCBS dies for the .38 and .30-06 until I could get my own. Not that I didn't like the RCBS, but I bought Lee dies since they were somewhat less expensive and I had good experience with my other Lee dies. Never had a problem with any of them. Granted, I'm not loading for bench rest competitions, but I think I'm doing OK. I have loads for the 9mm and .45 that are more accurate than I am, and a load for the .30-06 that holds 1.5" at 100 on a bad day and under 1" when the wind, the rifle, and I are all in synch. Someday I'll spend more time in load development to see if I can find a better one, but for now my time is better spent on other things.
I guess what I'm saying is that, as others have said, I've had good experience with Lee products. Frankly, if it weren't for the reasonable price and quality of the Lee products I've owned, I probably wouldn't be reloading as much as I am. I simply couldn't have afforded a high-end reloading setup until recently, and it doesn't bother me at all that I'm about to get a new rifle, and just recently got a new spotting scope, instead of having to choose between one or the other and spending several hundred dollars on a reloading setup.
I'm Just a Shooter, and that's Just my Opinion