I have recently used Precision Petrographics for preparing several batches of polished thin sections. Their quality is excellent -- no bubbles, correct thickness throughout the slide, and a good polish. I normally stain the offcuts for K-feldspar; and I appreciate the extra touch of their returning the "standard" slice they use to test the staining. Their turnaround has been better than I expected. Finally, communication with both Dustin and Sue has been excellent.