I use both programs, though, usually more Shareaza than Limewire. I always check to see each new version of Limewire and have been very impressed with their progress this year, especically the landmark of Firewall to Firewall transfers.
The main reason ive been using Shareaza more is because i find the program easier to use and i have a lot more control of the program. Also the library beats Limewire's hands down. On the flip side, i agree LimeWire does have more stable downloads and this is sure to improve even more in the future with F2F.