Bernies are great machines to sew with! I love my 1630 and would never give her up
I bought mine used about 15 years ago and then about 8 years ago bought a used one for my DD as a graduation present - she loves it too
This series of Berninas use the older style of foot (has two prongs at the top) and although some of them can be pricey they are solid metal and allow you to do so many wonderfully creative things. The Bernina home site has lots of manual info online and also info on what the different feet can do and how to use them.
I would jump at the chance for a 1120 - I suggest that you get it checked out and serviced to make sure that all is ok and then make a deal with your BIL based on the service bill - you won't be disappointed with this machine!