hi:
I have been using phpbay for a couple of years on my sites. the plugin works with the Eb*y API and updates auction listings within posts or pages that you create. so the post / page content is changing. the plugin does not auto create posts.
The plugin author is very responsive and there is an active and helpful forum community.
Currently i use a combination of: phpbay and wpomatic within a few of my sites. phpbay for shopping posts and wpomatic for news auto posts. as we know, wpomatic shares some similarities with wprobot in terms of auto creating posts from fetching rss feeds.
i can not comment on wprobot, as i do not use it. However I may buy it in the future.
Note: my personal approach >> wprobot is a complex plugin in terms of, it offers to do many powerful tasks. all of the tasks can be achieved by several independent plugins, some paid, some free.
I isolated the tasks that i needed to achieve in a autoblog and sought out the paid and free plugins to achieve the tasks. in this way, i am not reliant on only 1 plugin in the event that the plugin fails.
in my setup, i have spread the risk by imploying several plugins to achieve the tasks. if 1 breaks, then i find a replacement. but my site does not collapse. if wprobot fails, my whole blog would fail.
in short, phpbay is the choice for autoupdating Eb*y listings within posts or pages. and also provided coded protection from hackers and bots.
regards
redim