There's really no reason to not go with the junior if if you feel like the Gold is too much controller. It used to be that they limited the number of extra modules you could connect to the junior, so you would eventually run out of options. But they've upped it or removed the limit - I can't remember which. Either way, you can get the junior an then add the modules you want. You'll want the WXM to run the pumps/lights and probably the PM1 for PH.
Of course this will cost you more in the longterm....but many of the modules you would want to buy (wxm, PM1, PM2, leak detection, feeder, DOS) don't come with the gold anyway. So unless you are just itching to know your ORP or have a conductivity probe that is hard to get to work...go with the junior.
You will probably want to add an EB8..so that will be another $140 or so right off the bat. That will give you 12 outlets. The gold (I think that's $700) comes with an EB6...so you would possibly still need another EB4 anyway.