I now have a Croozer Kid for 2 trailer but still occasionally take the kids out the odd time on the rear seat. I toyed with the idea of getting a Yepp mini or the WeeRide but the standard rear mounted Hamax was what I settled for first. There are definitely benefits for front mount but also negatives. I found that when my girls were young that they wouldn't keep sunglasses on. Being in front exposes them to more flies, bugs, wind and rain which is especially an issue if they won't wear glasses. Of course there is the windscreen option too but they are dear enough. With my daughter behind, I take the flack!
If you live somewhere which is completely flat then fine, but if like me, you need to get out of your seat once in a while for a climb then this is made more difficult, if not nigh impossible. I have never had any issue hearing or talking to my daughter while she is behind me. We're not going at break neck speed (most of the time anyway!) so this is non issue. Her forward vision is blocked for sure but it's not a total eclipse. See is still regularly pointing out everything we pass. There is a bit of movement to how high or close you want the seat to be to you. I have never felt that having the rear seat has compromised my childs safety. Also when it comes to snoozing, she does it much better without getting buffeted by wind or getting blue bottles smashing off her head every few minutes. Also about the backpack comment above, I put her backpack on the back of her seat so neither of us are wearing it.
One thing is for sure, your child will absolutely love being on the bike. I actually feel sorry for kids who don't get to experience it as my 2 love it so much.
