Others have said it, but generally 1/2E (the two editions are very similar, with 2E being a moderately updated version of 1E although, of course, there are - still! - 1E players who hate 2E) is much more straightforward. I played it for 4-5 years and enjoyed it, but the total abritariness of the rules (dwarves can't be wizards; why not?) and the fact they relied on four or five different systems working together (totally different rules for combat versus ability score checks versus save checks) and had very limited use of skills makes them difficult to take seriously now.

However, it has been suggested that 1/2E actually encouraged roleplaying because there was little mechanical difference between any two fighters. Whilst the Feats/Powers of 3E and 4E make mechanically distinct fighters who can be very different from one another. Personally I'm sceptical of that claim, and the lack of choice was more of a negative. Though some would argue that 3E (in particular) gave players way too much choice and some of those choices (under-tested Prestige Classes in particular) were broken.