I think everyone will agree the 3G shoes are amazing comfortable right out of the box. I've heard the term "slipper" applied, and it's accurate. Now I hear that the TPU is very comfortable as well. How close is it to the 3G?

I have owed the Tour Ultras (had 2 pairs) and yes, they are very comfy, very well made, and they do sell replacement toe-caps.  I have attempted to change the toe-caps twice, and they both didn't turn out so well.  It seems that when you get the new shoes, the caps fit perfectly.  When you change them out, they only well it in small, medium or large (sorry, can't remember if it was S M, L or just 2 sizes) but they did not fit my size 10 shoe very well.  It seemed too long on the sole side, but the top seemed short and wouldn't fit flush and would leave a noticable gap on the top of the shoe.  Ug-uh-lee. 

I now own the Brunswick TPU-X, and out of the box, these are very comfortable, but I can't really say that they are MORE comfortable than the Tour Ultras.  I was impressed with the fit and feel, very nice shoes.  On my very first outing, I noticed that the TPU material on the toe-cap is very soft and not very durable.  It was already damaged on the very first outing.  Also, the front of the sole was coming loose due to the velcro not holding well and have since glued the front down to fix this.  I now use tape on the front where the toe-cap is worn down (works fine now, and it seems to have stopped the damage from getting worse) and the glue has been holding so that the front of my sole doesn't "flap" when I walk on the approach. 

Would I buy them again?  I'm not sure if I would spend that kind of money on either of these shoes.  Comfort wise, they are both great.  I'm only saying this because I am a toe-dragger, and i'm still looking for a very comfortable shoe with better toe-cap protection.

I had a pair of Tour Ultras.  Had problems with the toe cap.  As stated, the replacement toe caps are not exact fits and I had problems keeping the replacement on.  Then, as I have wide feet, the shoes started splitting on the sides and separated from the sole.

I now have a pair of the TPU-x.  Initial impression is that the Tour Ultras may have been a bit more comfortable but the TPU-x comes in wide sizes and has more plastic.  Only been about six weeks so will see how they wear.