I, too have had a little bit of trouble with 5.26: System Preferences seems to crash whenever the Screen Saver Options button for any XSS is pressed - but only if another XSS is first previewed or it's options inspected. So basically, if I launch System Prefs, go to ScreenSavers and then select an XSS, I can access its options, but if I then select a different XSS and try to access the options, System Prefs crashes. Still trying to track down the cause but may end up contacting the dev.
Overall however, the screensavers are fantastic like they've always been. For those having problems with the screensavers themselves crashing System Prefs when previewed, bear in mind that many of the savers allow you to set option ranges that your machine can't handle, no matter how fast it is. In that case, you'll probably have to trash the individual prefs file - located in ~/Library/Preferences/ByHost/ as org.jwz.xscreensaver.*.plist.