I started Right before 3.5 came out, which I'm glad I didn't buy any 3.0 books there were more holes in that than I care to think about, with that being said 3.5 isn't all that much better, once you get to a certain point (generally around level 9) it takes a monumental amount of effort on the part of the GM to kill you in that system, or one of the really nasty CR 20s who range from the somewhat dangerous to the utterly grotesque unstoppable killing machine, some of whom you have to be lvl 21 to beat because otherwise they will cast one spell and you will be done, permanently, Thor forbid anyone use their critters properly.
Now 4th ed is coming out and I've got a leaked copy of it, suffice to say while there all holes in the system you can drive a truck through they are almost all out in the open and awaiting you to just glance over them, for example some of the danger is back as monsters are tougher than you but you can hit harder, however the danger goes away rally quickly when you realize you have to go negative half your HP to die, which sucks especially for the higher HP classes because at a certain point they will find themselves at -1 HP with over 100HP to go before they die and they can't do anything but lie there unconscious. Then there is the whole AC issue, once you get around the level to face some of the big bads out there you will find that any of your meat shields have so much AC that the big bad can't hit them, unless they roll a 20, which also takes the concern right out of combat and players (well plate wearers anyhow) can throw themselves into the middle of any group of jerks and wail on them because even with combat advantage (the new word for Flanking, or an disabled target, something as simple as being caught flat-footed in 3.5 amongst other incapacitating effects) they can't touch you without a 20. I'm running a game this Saturday (I think) to test it out and see how it stands up, I think however there is going to be a bunch of FAQ coming out with the official release.