I'm using this approach at the moment with an Icon Original that I got for £80 from ProDirect.
I definitely middle more balls, and I also feel much more mobile/able to play more shots. For example, with an SH I really struggle to capitalise on legside deliveries, but with the harrow I'm pretty much on it.
Only downside is that I have noticed the lack of blade length at times. Shots that I would normally middle, I might toe, but I guess I'm still getting used to it. Harrow bats feel a little flimsier, and I'm not quite trusting mine against inswing into the pads at all, but hopefully over time I can begun to have faith in it.
I'd say buy a cheap one and have a go before comitting, though it has taken me a long time to even get close to getting along with mine.
To be honest, I'll see how the GM goes but will probably move onto my Mjolnir and eventually my new JpGavan bat by the start of the season.