My situation is a bit different from that of people who practice MSR or MJER. My sensei has taught me a little bit of batto (in this case the same as iai), but only as a supplement to the kenjutsu that I study. The idea is that if I spend all of my time using bokuto and fukuro shinai, it's possible that I'll build up some habits that don't transfer well; the batto is there strictly to acquaint me with the feel of a sword. For that reason, it would be fairly useless for me to use a bokken in my batto practice. I've opted to use a shinken for most of my training, as that seems the option most compatible with the spirit of getting me used to "the real thing." As other people have said, I think that using live steel has heightened my awareness and sensitivity in a very useful way.
David Sims
"Cuius testiculos habes, habeas cardia et cerebellum." - Terry Pratchet
My opinion is, in all likelihood, worth exactly what you are paying for it.