For the price i think they are brilliant, i have a fairly small head and despite what people say they do not fall off, i can play on my nintendo wii and wear the headphones at the same time. As for the quailty...
People say highs and lows are amazing...i do not know what that means, so in simple terms, its pretty damn good for a wireless set. People complain about the bass, but i find it more than satisfactory. There is a small hiss when no sound is being played, in some adverts and pauses in TV, but i feel that cannot be avoided considering they are wireless and only £45. Most of the time music or sound is being played so hiss is mostly unnoticable. If this does iritate you tho you can lower the volume, to a still 'hearable' level and not get any hiss.
The all round quality of the product i found was very good, however i found that some parts have lacked care on sennheisers part and could have been finished with a little more care. (i dont particulaly mind, but i is a bit plasticy, even though that does decrease weight.)
Weight is not an issue the padded band creates a comfortable set of headphones but the earpads are fully clothed and so can get hot after just under an hours worth of listening. I had an old set of wireless headphones with the much more logical donut earpads made from leather. I ripped then off them and surgically attached with velcro to my sennheisers.
The tuning only needed to be done once, i find can be accidentally 'untuned' which does annoy me but has no great hassle. The placement of the volume and the tuner within a square cm was a careless decision by sennheiser but not much hassle, one just has to think to feel for the upper scroll wheel when wanting to change the volume.
I am completely satisfied with my purchase and would recommend it to anyone, for its price i feel it is worth it.
BUT if i were to buy again, i would hav to choose the RS130's simply because the donut earpad is a VAST improvement in comfort and the auto tuning is an added bonus, it also carries an enhanced surround sound mode, which i feel could not really be much better than the as good surround like feel i get from these. But for a mere £10-15 i would invest in the next pair up.
However if your max is £40ish, these are the ones for you. They will definately satisfy ones wireless headphones needs.
Akash