I thought it'd be fun to revive this post since it never got a response.
I recently got a Venom Green Izula and after several days of carry ( belt/pocket ) I believe I can answer.
1. Weight. I was surprised how light this whole package is ( sheath and knife ).
2. Length. I have large hands and while my little finger isn't quite on the end of the handle its NO big deal. My strength is in my first there fingers anyway.
I feel a Kydex sheath would have been awesome it holds the knife securely. The knife in sheath is flat which lends itself to neck carry. Removal of the knife is intuitive and while theres no thumb ramp the knife is easily deployed. I dont think a handle wrap is needed (YMMV) which keeps the knife plus sheath light.
Adjusting your lanyard will keep the knife sitting in the best, most comfortable place on you. I've seen guys carrying lager (longer) neck knives which to me look cumbersome, again (YMMV). Added weight around ones neck can become bothersome over time. Cody Lundin I believe carries a Mora #2 which is longer than the Izual. Ones comfort level certainly plays a huge role is what is carried.
What role will your neck knife play? I think this is the primary question you will need to ask yourself. While size and weight are important as well as small light knife may not be up to the tasks you want a neck knife for.
Here are some examples I have. CRKT Minimalist, SOG Snarl, Mora Classic 2, Esee Izula, and Mora Eldris.
Both the SOG and CRKT are fine knives BUT I wouldn't carry the SOG for anything outdoors related (hiking, camping, fishing, backpacking) but thats me. I don't think its development included those anyway. The CRKT is a great little knife. I know there will be some that feel they can accomplish most outdoor tasks with a very small blade and cudos to them. The difference between the CRKT and Izula is noticeable in use ( to me ). Its not just overall blade length its shape as well tho length IMO is significant in use. The Elder is a little blade. Whats interesting is inserting the knife into the sheath gives you a longer handle but the blade is still small. Its my partners neck knife and she loves it. She carries a Mora HD for her belt knife so the Eldris is her "fun" knife. Fire starting, whittling while sitting fire side, etc.
I wont even compare the Mora Classic as the length is significant as is the overall knife.
I feel the Esee could make a great neck knife. Great reputation on their 1095 and IMO fantastic overall package. The other knives are also nice in particular the Mora Classic is a proven blade with scores of fans and users. I dont have the proper sheath but Cody Lundin seems to have made a great neck carry out of his Mora.
Its all going to come down to personal comfort and what the necker is to be used for. Hope this helps someone.