I made two items - both about 7.5" x 7.5" x 5.0" without problems. It did take a long, long time.
One of the items is on my Harley - photo attached.
In terms of file size - I designed several parts with knurled handles and features that resulted in file sizes of 90 meg. Simplify3D had problems with large files sizes (not uploading well). However, I solved that problem by increasing the Simplify3D cache size, the communication timeout and baud rate.
Later, I changed the .stl output in Solidworks to make smaller files - still good parts and 80Meg files are now about 3meg.
Post's attachmentsair_cover3.jpg
air_cover3.jpg 185.65 kb, file has never been downloaded.
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Mac OSX ElCapitan
Prusa i3 (two built from kits), 1 hacked DaVinci
Solidworks for models, Netfabb to repair, Repetier/Slic3r and Simplify3D