I got the standard lid and added a claymore. If I had to pick between those two, I would pick the XTL. The XTL seems like it has more function for a bivy hunter and I like its layout moreso than the longhunter
Standard, I didn't need another pocket or 2 for the weight. The pockets on the front of the pack function like a top lid for me. I would go with a standard and a pocket for on top. It's lighter, more modular, and cheaper
FM, it really depends on your needs. If you like the added feature of pockets of the XTL more than the simplicity of the Standard, you have your decision. Depending on which pack you have, you don't always have to take the lid. You can fold up the top and close it up or put something on top of the pack like a tent or pad then cinch it down. Or you could just be sick and own all three like I do, then choose which one you need on a particular trip.
i got mine with a standard lid and a claymore lite.i did this more for the versatility of having just a lid when the extra space is not needed.that being said i will pick up a XTL during my next round of gear buying (i do it in waves)
I have the standard lid and the Longhunter lid (from my Longhunter). I don't have an XLT but in looking at the online information the Longhunter lid has more cubic inches than the XLT but weighs a couple ounces less. I know the Longhunter lid has more cubic inches that a long pocket or claymore and looks to have at least as much if not more space than my KU E&E. One advantage of the Longhunter lid is that it can be converted into a lumbar pack. It has a waist belt and a shoulder sling. You can even attach the gun bearer to it while setup as a lumbar pack.
I bought my T1 with the standard lid because I wanted the lightest configuration and I felt the outside pockets on the T1 were enough for my "easy access" stuff. I've found that with my T1 in day pack mode I can put some stuff (such as my rain gear) in the sleeping bag compartment even though it is fully compressed. Thus, I have 3 zippered pockets for stuff that I can access quickly without having to open up the main bag or adjust compression straps.