I went through a similar conversion early this year. I swapped an Osprey Kestrel 48 and REI Quarterdome 3 for a Zpacks Arc Blast and Hexamid Twin.
My guess is that there are several tents or tarp/bivy combinations that would work, but this one is light and very easy to set up. I have had my 60# dog in it with me and had plenty of room.
For the back, it is a semi framed back that really seems to make the pack feel lighter. I am typically in the 15# range and it is like nothing. I have had it up to 29# and it felt like a 20# pack.
Overall, great quality and excellent options for customization made the cost worthwhile for me.