Personally, I’d go with the Tengu. If you use a travel fit, it’s significantly safer for traveling, and should give a decent little bump to isk efficiency. That being said, I also feel rather confident in my ability to avoid unwanted PvP (i.e. I monitor intel channels and local, stay on comms, remain attentive, set up bookmarks when appropriate, and all that jazz). If you feel less confident, you can start with an ishtar, and move on to the tengu later. Use the time you spend in the Ishtar to get good at avoiding PvP, and run enough sites that they become an automatic task for you. Cognitive psychology research shows that attention is a limited resource, so familiarity and comfort with the PvE side of things will mean you’ll have to devote less attention to that, and can devote more to situational awareness.
Also, if you have a question about application, you can plug fits and rat specs into pyfa, and then create damage graphs to see which ones apply better. You’ll need the rat names in order to look them up, and you should figure in their expected behavior when plugging in stats. For example, if you plan on kiting in a turret ship, rat transversal will likely remain quite low, so you shouldn’t set their angle to 90 degrees. If you plan on kiting them in a missile boat, you should plug in their chase velocity and not their orbit velocity. And so on and so forth. It shouldn’t be too hard to figure out with a little common sense.
