Netsim problems

in CCNA & CCENT
Well, after configuring a network in netsim, (took me several hours) the bloody thing only saved half the config, then on reloading the lab, it lost everything. I've noticed other bugs as well.
I've come to the conclusion that it's only good for practicing typing commands and for creating simple configurations.
When will somebody come out with a perfect router emulator? It's not much to ask is it?
I wonder why Cisco have never developed one?
I've come to the conclusion that it's only good for practicing typing commands and for creating simple configurations.
When will somebody come out with a perfect router emulator? It's not much to ask is it?
I wonder why Cisco have never developed one?

Data, Segments, Packets, Frames, Bits
Comments
My version is 806, the updated version is 831
I was able to save all the settings by going to file - - >save multiple device configuration.
I agree that there are some bugs… but should be OK for the CCNA preparation