I have just ordered a gencon all in one for the puppy, who's just starting to pull a bit on the lead, especially when I'm walking both dogs.

Was wondering if anybody uses one and what their opinion is, good or bad.  I like the fact that one size fits all and that the collar/lead will still fit when the pup's full grown, so I wont have to keep replacing as he grows.

I don't want to use anything too severe and I find that a gentle leader somehow always manages to ride up near the eyes which can't be very comfortable for the dog.

 

We recommend these at work along with walkeze harness's, i like them because they dont ride up & rub the eyes.
The thing i like about them most is that they are self righting, ie. if the dogs pulls it gets tighter so when the lead slackens so does the fitting around the face so i suppose you could say that it rewards the dog for having a slack lead ( i would reward this anyway too with a toy or treats )
Obviously it goes without saying that you should never yank or pull on these as that could really hurt & jar the neck.
I would personally get any dog aclimatised to wearing one by gradually introducing it & making it very rewarding. Put in on for a few seconds & treat , take it off ect & build it up, play with the dog while its on & then hopefully your dog will look forward to you putting it on, rather than claw & scratch at its face to get it off.
HTH i know i' not too good at explaining things

Having used both and tested many other similar training aids I would say the Gencon is kinder for exactly the reason you mentioned.  However, the best way of getting your dog to walk without pulling is to train it without the use of 'aids'.  Maybe you will have to walk your dogs separately at first while your young dog realises what is expected of it and then put them back together.