Kelly - Mo speaks some good words of wisdom. I have not owned the iS40 but I did own an iX300, which I thought was very well built and had great features. Again, keeping in mind your budget you are not going to find something with USB storage or probably not even a harmonizer. Putting those types of frills aside, arrangers from the last 7-10 years are very much in the mainstream of technology.

You speak of 'synth mentality.' Most mid to high level arrangers are great synths in and of themselves. IMO arrangers have a step up on regular synths because they were the first to group sounds into easily accessible families with dedicated buttons - much easier to use on the fly.

Your language seems to imply a very intelligent person, so if you've found your way here to the SZ, keep asking questions and you will finally get the answers you need. We can wait for you to take your turn at reviewing and answering; it won't be long.

Lastly, don't let the manual chase you away. You can learn so much right here tht the manual will become some place to begin your search, not end it. Anyway, these arrangers have so many features that you may never use or need them all.