I just dealt with this decision myself, just a few days ago. I spent 2 or 3 days agonizing over which to buy, since at this time I really could only afford one or the other. I liked the tailstanding ability of the Pro (Regular) and I liked the quick access to all modes. However, I did not like having to ever set eyes on the strobe/SOS modes (might be helpful someday but I find them to be useless at this point in time) and I didn't like that the Pro version lacks momentary on, although this is really only a minor issue for me.
The Tactical, on the other hand, has ultra-quick-to-access dual programs which is great when you want the light to come on in the same mode every time; no fuss, no muss. I also like that the tailcap switch is easy to reach and engage, as is the momentary on ability. The rubber boot on the switch is obviously more exposed than that of the Regular version; if you're pocketing it, it might be best to relegate the light to its own pocket to avoid wear and abrasion from other items (like keys). Another downside to consider is that there will probably be times that you'll want one of the modes that aren't programmed, in which case you'll be bezel-twisting and clicking like a madman to get the one you want.
My choice ended up coming down to availability, which is nice: I was so torn between the two that I was relieved when my chosen online store only had the Tactical version in stock. Now that I have the Tactical, I'm confident I chose the right model for me. I don't think I'd like the Pro as much. I definitely appreciate the protruding tail switch as it's very easy to engage and the momentary on is a nice feature, even if it's not crucial to me. I also immediately came to appreciate not having to swim through the strobe modes to get to where I want. I wasn't entirely sure how important this was going to be but now I don't think I could live with the alternative. I only wish the Tactical hid the strobe settings completely, but I know then it wouldn't really fit the "tactical" moniker as well.
I've got my Tactical set up for Moonlight mode and Hi. I do wish it had a third setting for max, but that's pretty much my only gripe. I also came to realize that while tailstanding is a nice feature, it simply isn't that useful to me, day to day. There are all kinds of things I can do to stand my light on its end, regardless of the switch type. I'll gladly take the two program modes of the Tactical over the Pro's tailstanding any day.
I started typing this before I left for work this morning and just finished it now, so some of what I stated is probably redundant, but there ya go. Hope it helps!