Yup I also tried the 428's and the 439 are a whole leage above them and majorly more comfortable too. The 428's were painful in a relativley short time.
I got these Hd439 refurbs from VMInnovations for $45.xx with a 5% coupon found after liking them on FB.
They look new and come with both cables. Super happy with these after buying about 5 sets of cheaper cans: HD201 (comfy), HD428 (painful), some JVC's (painful).
The 439's remind me of the HD580's I had years ago but couldn't drive properly.
I'm using a HiFimeDIY Sabre Tiny USB DAC (ES9023+PCM2706) to drive them directly.
They also have an easy mod (removing middle tape covering whole behind the driver) which raises them to yet another level.
Great buy, don't waste your time on lesser models is my advice