This provides the perfect balance. You can use multiple currencies, have fully flexible renting periods. You can have calendar views or table views of your availability with or without prices.
You can define extras, e.g. towel packs, extra beds and price them each, by week etc.
You can set discounts for multiple booking periods, and setup a payment schedule (e.g. 30% on booking, balance 4 weeks before etc.)
You can choose to show booked periods or not, show unit descriptions or not, provide text before and after the calendar/table.
It has flexible forms built in to capture enquiry/booking details, flexible email options.
There are a few reports available too, though I haven't used these yet.
You can enable online payments through Paypal/moneybookers or the system is very useful even without this.
It also comes with the most important thing - good documentation and a developer who takes pride in his work, and fixes bugs quickly.
Rentalot Plus is incredible value too.
Can't recommend this highly enough. Thanks Chris.