There's many threads on 029 and 028 on AS...
They are both fine saws. One is 15 years older, and a 25 year old design (the 028). The other (029) is more powerful, but made to be less expensive to manufacture (one piece nylon tank/engine mounts assembly) and is harder to repair when performing major overhauls. Some on AS call the 029 a "boat anchor", but it's one of the best selling mid-size saws and the typical homeowner loves them. On the other hand, the pro's hate them. The 029S is almost what is now sold as an MS310 and it's a decent saw typcialy sold with a 20 inch and 3/8 bar.
I really like the 028 Super - the last version made - it's similar in construction to the next generation of saws - the 026 / 036 etc. The early 028WB are o,k, but lack power, have no chain brake, and have aluminium tanks that have a number of problematic fracture points if abused.