Forget the autocal it is not worth it and you will not get the best picture with it. DIY vs. Pro really depends on how much time you are willing to spend learning and performing calibrations. A pro will usually use better equipment than a colorimeter, at least for profiling so their results should be more accurate. That's not to say colorimeters are bad, they are not. They will still give you a very good picture. They have trouble with some displays but typically do pretty good with most projectors.
Calibration is like anything else, for example yard work. Some people enjoy doing yard work and spend a lot of time doing it, some pay other to do it, and some having a pristine lawn is not a priority to them. If you enjoy tweaking and spending hours doing it then the DIY route is probably for you. Plus then you can tweak it as your bulb ages, get a new bulb and have as many settings as you want for different viewing conditions. Plus you can use it for other displays. If you don't enjoy this tweaking time then a pro is a good option. If you are happy with it now you could do nothing, ignorance is bliss. There is a noticeable improvement with calibration and this projector.
A good option for a lot of enthusiasts is to do both. Get the equipment and start trying to do calibrations and get familiar with the equipment, then hire a good pro that is willing to explain what he/she is doing. This is a lot less expensive than an ISF or THX class for learning calibration and it will definitely decrease your learning curve time and help avoid mistakes.