Some people don't like the feel of the suspension when pedalling hard but if you pedal with a fluid efficient style there's no problem, and in fact it encourages good pedalling IMO. To counter this I've seen some people when they first get a Moulton run the front suspension with a lot of preload, but the suspension actually works when run relatively soft, with appropriate damping.
I wonder which front suspension spring people are running, the firm or the (stock) soft? I'm a lightweight (62kg) so imagine it'll just come down to personal preference in the end. Being so lightly built though means I have no option but to spin up climbs, and am not generally one for standing out of the saddle except perhaps to crest a small rise, so I am hoping that the front suspension and I would get along just fine.