Been using Regular and Pro on my main for about a year now.
Regular is good, everything you expect from most ebooks - aim, esp, I think inf ammo is included but I don't remember anymore. However, if you put a ton of hours into Destiny (like its your main game), you need to consider Pro. It has a ton of PVE features that make you feel like a super guardian, instead of just a regular one. Faster grenades, faster melee, faster class ability. Faster super. Inf ammo is great, along with the ability to set how much ammo is in your mag. With it set at 1, you can take advantage of perks like High-Impact Reserves, which gives you +30% damage on the last bullet. It's a nice way to be OP while still flying under the radar.