Series 1 chips are easier to use for most purposes. They provide direct I/O port manipulation. However they don't allow mesh networking. They are only point to point and point to multipoint. Mesh networking allows the signal to be relayed through multiple nodes before it gets to your final destination. If you absolutely need that capability then get series 2. Otherwise get series 1.
As far as chip/wire, ive only used the chip ones and have never had any problems with them, but I haven't done any range testing so its kinda hard to say. If you want to push the limits of the range you might want to go with an externally mounted antennae.