I like their 50' boxcars (pre-plug door cars); I used to have a whole bunch of them when they were kits you assembled yourself (easy to do). Some were under the regular Weaver brand, others under Quality Craft.
I now only have the Railbox cars (including factory weathered ones) and a BN one as the specific prototype FMC boxcar Weaver chose was specific to RailBox, although BN had a very similar one that was plug-door type. The rest that were other roadnames were gotten rid of.
I also like their 57' modern mechanical refrigerator cars. I like them even better than the Lionel version for the following reasons:
1) The Weaver door guides aren't grossly oversized like the Lionel ones (downside is the Weaver car doors don't open but that doesn't bother me like the oversized Lionel door guides do)
2) The Weaver car has a simulated roof-mounted exhaust stack; the Lionel lacks this detail (where is all that diesel engine exhaust going on the Lionel car, under the frame like an automobile, LOL),
3) The Weaver car simulates the cushion underframe the actual prototype has, which the Lionel model lacks.
I also have some of their modern 3-bay and 4-bay outside braced coal hoppers and some of their PS-2 hoppers which are all nice.
All I have converted to 2-rail operation for looks.
Having said that, outside of the 57' reefer cars, I haven't bought any Weaver cars in a long time; mostly because I prefer more details that Atlas O, Lionel, and MTH have come out with the past few years on their scale freight cars.