I have had the AC Jr and currently have the ACIII. I really like the features of the Aquacontrollers. I did a lot of research and the one thing you need to look at is growth potential. There are limits on the ACJr as far as thenumber of items you can control - don't forget the Actinics, MH and Moon lights though all housed together is some light packages count as three items - then you have the main pump -heater-skimmer-etc. I ended up with the ACIII becuase you could program alot more and you have access to the unit via the web to make programming much simpler.
The ACJr is a great controller, you need to determine if you want the serial interface as you can't add it later.
On a customer service note - NEPTUNE Systems has been really responsive when I need a bit of an assist with the function of one of my DC8s.
WHile the automation is great, I would think that for a 30 gallon you could spend $300 on other upgrades unless you are trying to controll too many things. You at a minimum have to have the ACJr unit and one DC8 which is $279.00 on the web.
Have any other questions, let me know!