As a collector of currency issues pennies only, here's why I shy away from proofs. There are far too many scarce years and types within the penny series that can keep one so busy for a lifetime that the presence of proofs is best seen as a nuisance. Further unlike Silver and Gold, Copper and Bronze coins react pretty much with anything and lose their mint state. So to find something that has beaten the odds to survive in good nick is something I (personally) find fascinating. Consequently the tendency is to go for the currency issue because out of many thousands a handful have survived in decent grade as opposed to the 3 or 4 proofs made for the same year that are all probably still fine and dandy after spending time in a safe somewhere. This is possibly why proofs of some years are less expensive than the corresponding currency issues (think 1950, 1951, 1953 etc). I recently came across an 1895 2mm proof that sold for lot less than an 1895 2mm currency version in unc. Further most penny collectors are obsessed with varieties, one of every type is better than the sharpest or shiniest and this obsession feeds into the next generation automatically or the minute one unwittingly obtain a scarce variety. The joys of Penny collecting .....