The learning curve is very steep.
It's admin user interface is not well planned or thought out.
Support has gone downhill.
New responsive design release is now 3-5 months overdue with release date still not set.
Those above are my main complaints. I have been looking extensively at eCommerce solutions for Joomla, even looking at Magento, but it's clear that Redshop needs a lot of work to compete. They still are coming out with for-sale templates yet they can't fix the bugs in their cart software that have been there for months.
I spend way too much time trying to deal with their support doing half the job, or answering half the question that I ask, or even responding to a completely different question than what I've asked. I'm waiting weeks for them to fix bugs, it's too much.
I am switching to Mijoshop after this last experience is over.
It can be used as either a module or a component, but keep in mind to use the advanced features like putting an anchor link around a slide you must set up the slideshow to use the component instead of folder source, and then go to the actual component to build the slider. That seems to be a little tricky to newer people trying to use it.
I definitely would recommend this to other people who need to put a slideshow in their site.