In a bout of great timing I picked up the latest issue of Can4wd today and there was a tiny article on this, the editor explains that it is more in regards to lift than tires (I feel these are closely related) he says that 4" or more go long anything under go short.
Here is a snipit from the mag:
"General rule is anything over 4inches of lift and you should go long arm. Im not a big fan of long arm systems unless you run a 35 inch tire - or bigger. With t33's the arms hang very low and will actually drag more than a short arm Jeep.
The main reason for that height and over for long arms is you end up having a steep angle on your arms and the ride height will get choppy on the street and as you try and climb anything off road your suspension will want to plow ahead rather than push up"
Page 10 if you pick up the mag.
I have heard of this several times and it was my main reason for staying with the short arms as I do not plan on running larger than 33's for now,
There are members here who will be able to provide more information as they are paid for there advice in skill when it comes to suspension tech...... last time I checked I am not, feel free to donate if you like.
After doing my research, my determination and opinion is to stay short under 35's, but there may be better alternatives and different ways of setting up a long arm suspension to provide better results with no negatives.