A little backstory first...
Ed Wood will always be associated with incredibly inept directing,amazing goofs and plotholes and unintentionally comical scripts,taking on all-comers for title of worst director ever.People like Uwe Boll(House of the Dead,Bloodrayne),Paul Anderson (Resident Evil,Aliens vs Predator) and Hal Warren (Manos:the hands of fate,luckily his only film) may challenge Ed,but,at the end of the day,Ed remains as king.
Plan 9 is considered by many to be his magumn opus (I believe that even Ed described Plan 9 as his Citizen Kane in his diaries)
and,well,everything you've heard is true.Yes,Criswell really does say "Future events such as these will affect you in the future",yes,Bela Lugosi is mostly played by a obvious stunt double (Bela died after Ed shot two minutes of footage) and yes,the string holding a UFO in mid-air does catch fire.
However,this is an essential purchase for any film buff's collection.To be the worst film ever,it would have to be devoid of any entertainment,which Plan 9 has in spades.To really watch the worst films ever,just hunt down any of the thousands of straight to video horrors that come out every year.After those,you'll be glad to go be to Plan 9.
In short,if you want a film to enjoy with your friends and to laugh at the lack of quality control,buy this.
If you want a masterpiece of film making,a classic that is universally regarded as a piece of art,avoid like the plague (But who actually watches that kind of film?).