I think there is a place for the add-on, if it can be made to work well enough.
For me, there is a definate use of having a program where you enter your desired changes to your orbit, and an autopilot performs the burn. There is something about flying a Space Shuttle, or even and XR-2 for me, and controlling the engines with a throttle....breaks realism for me.
I have been using DVTools, which takes in data (like how much I want to raise my apogee for example), and spits back out data that I enter into IMFD and it does the burn for me. From what I have experienced, with all the gravity options on, STSGuidance will always fall short in its burns, mainly becuase I think it calculates what it is going to do well in advance, and then never changes its plan, so you end up in an orbit far from what you had targeted, and I find DVTools an easier thing to manage, trying to stay ahead of any sort of madness nonspherical gravity unleshes on my path.
However, the rendezvous ap does appear to work failry well in similar circumstances.
My issue with it is that it doesn't quite do everything in the manner I would like them to be done. For example, I do not like how it orientates the spacecraft for height burns. If there was a means to control that, it would be a bonus. I do not like the manner in which it flies the rendezvous. If it could be tweaked to fly the path the Shuttle flew to the ISS and put me on an offset X meters on the R-bar, that would be even more useful.
There seems to always be a crop of new orbitnauts that have trouble with certain concepts which I think the idea of an auto rendezvous AP would sound very attractive. I myself, like I said, would only use it if it behaved a very specific way, otherwise I'd just stick to my current procedure. There is not a singular add-on available that I would say is "better", but there are enough quality stuff out there, that when used in unison, can far exceed the capabilities in terms of control and precision of these manuvers of Guidance MFD.
For some the idea of using 3 or 4 or even more MFDs during a task is a bit daunting, for others (myself included), it is no big deal. But of course, in a perfect situtation, a singular program has to be the preference over a multitude, but I am not sure how far you would be willing to take this thing.
