From personal experience i can tell you this...whatever you make...it will sell. How many sales depends on what you put into it.
Some things to think about...
RTI comes with a good UI built right into the software. This means you have an uphill battle right out of the gate.
Everyone has a different idea of what "good" looks like. Some people will love your design and others will hate it. There will be no convincing those who hate it. Embrace those who "get" your vision.
People will pay for things that make their lives easier. The more example pages you have the better. You will need to build for iPad/iPhone minimum. Its also probably a good idea to find out what the most common android resolution is and build for that too.
Keep the file updated. Give purchasers free access to new icons and example pages. Use a newsletter to let them know about updates. This is something i wish i had done. It gives you the ability to inform people about new products while reminding them how you are still actively supporting their original purchase.
I think it looks great so far. Floorplans are cool but you will need to use room buttons for a commercially available UI. Some houses just wont fit on the screen properly so even offering free floorplan graphics wont work.
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