You have to look at the "Pros" and "Cons" of the choices. Here are an article and a review regarding the differences between the VideoMic versus the VideoMic Pro. They cover the bases well.
http://www.komar.org/faq/camera/rode-videomic-pro-review/
http://www.soundonsound.com/sos/apr11/articles/rode-videomic-pro.htm
In essence, the 'Pro is smaller & lighter, the polar pattern is a smidgeon closer to being a true shotgun than the original, and it has a +20dB gain switch.
One thing to keep in mind is that both are High Impedance (Hi-Z) units, so cable runs of more than 10 feet might introduce RF (radio-frequency) and EM (electromagnetic) interference from cell phones, appliances, etc.
If you are going to have someone else act as PSM (Production Sound Mixer) and "swing the boom" (Boom-Op) then an audio recorder may not be a bad idea. However, if you are going to be "flying solo" forego the audio recorder; KISS - Keep It Simple, Stupid. Also, if you are flying solo, the wider polar pattern of both VideoMics will be more forgiving than a traditional shotgun mic.
Good sound is not about the gear; well, it is, partly, but it is really about the skill with which the gear is used. Great sound is about obeying the laws of physics and preparation. The physics is when the mic is further away from the sound source less of the desired signal will be recorded and more of the surrounding ambient noise will be picked up. The mic also needs to be aimed properly. The "best" production sound is when the mic is aimed from above at the base of the throat rather than directly at the mouth; more chest resonance is picked up by the mic giving the voice more body (pardon the pun).
Prep is selecting locations for sound, planning for sound during prepro, treating the set for sound, discussing sound with wardrobe and props... the list goes on.
Hope this has helped.
