Can't say whether it is "best" or not but:  We have a Lexmark Optra S1620 and it has been in service for 5 years.  I can print on both sides if I want. This feature has saved a lot of paper  It is a fast machine and I have had very few problems with it.  The firm that sold it to me had to set it up (kind of a lot to it).  This is a bottom feed machine, but I doubt Lexmark would like to hear them described as bottom-feeders.
 
I also have several of the HP top feeds and have the same aggravating problem with several pages pulling through at a time.  
 
I guess I got what I paid for.  The difference between spending $2200 and 300 per machine.  (1998 prices).   If people are fairly close, it could be set up as a network printer.

We had the same problem with all of our HP top feeders until I discovered that HP has a fix for the problem and it's FREE!  Just go here and request as many kits as you need:
 
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=bpl10045& amp;locale=en_US
 
We had mostly LJ 5L's which aren't listed, but the LJ 6L kit worked perfectly and now none of our printers feed multiple sheets.  For some reason HP didn't widely publicize this fix, and if you contact them, they will blame the paper or something else, but this fix cured the problem for all of our printers.
 
We have since added some LJ 1200's and like them a lot.  They are fast and inexpensive.
 
Les Edelberg
Filter Concepts, Inc.
DBA since '94

We also have the Lexmark Optra S 1620 and are extremely pleased with it. One of the really cool features (though we rarely use it anymore because we use PDFs) is the ability to print more than one page per sheet - like 2-up, 4-up, 6-up, etc. It really saves time and paper if you're printing something for archiving. Even 4-up is readable from 10pt original.
 
Our top-feeding HP also has a problem with multiple page feeding, but usually only when it's really humid.

Now that I ordered my HP Fix kit I read the instructions. It's just because the scrubber pad that holds the rest of the paper back is apparantly made out of rubber that hardens faster than it ought to. Hopefully they've improved the one in the fix kit, because you can only replace it once.
 
Anyways, I guess that it will prolong the life somewhat.

Les,
Your "fix" for the HP's sucking multiple sheets has been a life saver in our office.    You are a hero.   I never had to purchase that new printer.   Installed the "fix"on (3) HP's right after your initial response.    And it looks like you helped a bunch of folks.    
I was also glad to know it was not a DBA issue.
Many Thanks,
Laura
 
Les said:
 
We had the same problem with all of our HP top feeders until I discovered that HP has a fix for the problem and it's FREE!  Just go here and request as many kits as you need:  
 
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=b pl10045&locale=en_US  
 
We had mostly LJ 5L's which aren't listed, but the LJ 6L kit worked perfectly and now none of our printers feed multiple sheets.  For some reason HP didn't widely publicize this fix, and if you contact them, they will blame the paper or something else, but this fix cured the problem for all of our printers.  
 
We have since added some LJ 1200's and like them a lot.  They are fast and inexpensive.  
 
Les Edelberg  
Filter Concepts, Inc.  
DBA since '94  
 
 

We use Brother HL-1440 laser printers. They are great! I believe there is now a model newer than that, but we never have any problems at all, even if we are printing out extremely large reports.  Also, Brother's tech support has always been very good at helping with any problems we ever had (very few).  I would strongly recommend these printers to anyone.