Here are some bugs introduced in beta 4.9.0 that are still present in 4.9.4.

• Hitting "resume" on a file "awaiting sources" no longer attempts to connect to known, but busy, sources of the file. Doing this caused Limewire 4.8.1 to make an honest fresh attempt to connect to most files, occasionally resulting in a download. In all of the betas, it does nothing whatsoever.
• Stderr console frequently shows warnings such as "ignoring cancelled key" that did not occur with LW 4.8.1. What impact the cause of these warnings has on the app's functionality is hard to determine but it's doubtful it's any good.
• For some reason, the sort order has been changed so that when downloads are sorted by status, files waiting in line no longer sort last. Busy ones now sort last, and files waiting in line sort second-to-last. This seems to be related to a change in the wording for files with busy sources.

Longest-standing headaches still present in betas that were also present in 4.8.1:

• Sorting by status makes download list items jump around -- which is OK until you try to select a specific item, and it always interprets your mouse click as occurring one jump later than it really did. The real problem is that mouse clicks seem to be ignored for a time, then treated as having just occurred, instead of processed immediately. Fix: Boost the UI event handling thread to highest priority to it preempts all other Limewire threads when a UI event is generated.
• Sorting a large download list by name is slow. What are you using -- bubble sort? Use quicksort -- it comes with the JDK so there's no excuse for using anything quadratic like bubble sort.
• Mem & CPU use are still high, though better in the recent betas.
• The icons on search results still all seem to mean the same thing, that being "It's anyone's guess whether you have the file already or not, and if not whether it's going to download quickly, slowly, never, or it already is". Is it even possible to get it working? The number of failed attempts so far suggests it might not be, in which case replacing them with something actually useful, such as bitzi ratings for the files, might be a better idea than trying to fix the current icon system.
• It still freezes for a short time sometimes when initiating a search, especially after a period of inactivity, and when downloads complete. Clearing a bunch of duds out of the download list with a mass select and cancel download, or with (do not click this button!) clear inactive, causes the UI to hang until you force-quit Limewire.
• There is still no "No to all" on the overwrite prompt, or "remember this decision" check box, or similar feature. It is sorely needed. (Unless by some miracle you get those icons working, especially so that green checks appear beside all and only the files you already have. Given the current track record, this seems unlikely -- all the failed attempts to fix those icons suggest there are deep technical reasons making fixing them lie somewhere between "difficult" and "impossible", whereas adding the requested functionality to the overwrite prompt is probably a two-minute job.)