Soft modding sucks nuts.
90% of all big problems that you ever hear about modded Xboxes these days come from fools that soft modded.
Fortunately for me I bought both my Xboxes back in the first year, and don't need a modchip or softmod thanks to a nice 1MB TSOP, but if I were to buy one of the newer Xboxes, I would no doubt get a chip for it.
I guess as long as you are very careful, you won't have to worry so much about f'n up your softmod, but with a chip, there is no worry at all, especially when you have multiple banks to boot from.