Are you buying new or used?  I only ask because those appear to be discontinued camcorders.  I've only used one JVC Everio camcorder and I didn't like it but that's not to say that the one you mentioned isn't a good one.  Between the two I would go with the Sony.  Honestly though I'm not real fond of either since they record to Micro SD cards.
If you are looking for something in the $200 - $300 range then you might want to consider one of the following:
Panasonic HC-V250 Full HD Camcorder 
Canon VIXIA HF R500 Full HD Camcorder 
Canon VIXIA HF R600