Here's something to be on the lookout for... not specifically with WennSoft, but with ANY job costing system:
How tough is it to set up a job?
Many users want a job costing system, but for small and/or unique jobs, it takes a lot of work to set up the job, steps, resources, bugdets, users, items, hours, start date/end date, overhead...
All other things being equal, a job cost system, in my opinion and experience, is easiest to use in an environment where there are standard, repeatable jobs, with standard materials, pre-defined labor hours, standard overhead, etc....
As far as WennSoft goes, they've been around "forever" and have won many awards from Great Plains... but like anything else, depth, power, and richness of features takes some time to set up.