Now i have both DIY'd and bought some pinhole equipment, my initial impressions:
1) The larger the format is definitely better: my 8x10 sheet looks awesome. But the 4x5 sheet and 6x6 medium format shots are plenty good too.
2) DIY pinholes can be quite good as well: I used needles, sand paper and later micro drill bits. Using a high resolution flatbed scanner (Epson V700) is a good way not only to measure pinhole size, but also to inspect pinhole quality (roundness). The pinholes from RealitySoSubtle is very good and reasonably priced (shipped from France).
3) My current favorite is the Agfa Click converted pinhole: super light and compact, curved film plane, super easy to DIY convert (only 4 screws), and all together fun.
I'm still waiting for the Vermeer 6x17 to arrive, as well as starting a DIY project for a super compact 8x10 pinhole (9x12x3" folded, 9x12x6" open). Stay tuned!
One example photo from Agfa Click (0.2mm diameter pinhole, FFL about 50mm)
Bear hug downtown SF - AgfaClick_50f250_Ektar100A_008 by
Zheng, on Flickr
My first 8x10 pinhole sheet from Deardorff V8 (0.5mm diameter pinhole, FFL about 150mm, shortest the bellows allow)
Tulips: first 8x10 pinhole - LF810_017 by
Zheng, on Flickr