First, avoid the original DR-100. The preamp in the DR-100 MkII is better.
The R-26 has a quieter preamp than the Dr-100 MkII, but it's much larger. The R-26 really isn't a pocket recorder. The DR-100 Mk II has S/PDIF digital input, the R-26 does not. This may or may not matter to you. Neither has particularly good built-in mics, but you're probably considering these for XLR input, not for their mics.
If you can wait two weeks for the Olympus LS-100, it's worth considering, even if you don't need the muscian/composer features.