much depends on whether or not you have hard or soft water. I prefer clear glass. There are many simple glass cleaning products. Glass block shows spots less, however. But it does not open up the shower stall - it feels more closed in.

Glass block requires minimal to no cleaning when compared with regular glass. It is not difficult to clean regular glass however but cleaning a glass block shower or wall takes a much less toll.

Good points Mahoney Architects and Eastern Glass Block. It should also be noted glass block come in clear patterns now as well. I'll include an image below which shows both see-through and clear glass blocks. In general the glass blocks (especially those with patterns) don't show spotting like a clear glass (or glass block) wall