Over the last months this has been discussed a number of times so it may be worth doing a search. We are currently replacing our existing system and did a selection process from 5. In my experience it really depends on what you want the system to do, how you want your reports, who needs access. I was very keen that every member of staff could report an accident, deal with an action and view/edit risk assessments which made licensing an issue. To enable this to happen we found an organisation (Health+Safety is the product) which provides a universal licence option which was very cost effective, I also like the automatic reporting. During the procurement in general each system was very similar in what they offered but there were differences in visuals and useability - we saw 1 which we loved but felt was too complex for our organisation. Not sure that this helps but be very clear in your must haves, desirables, what you don't want the system to do and weaknesses that need to be addressed as well as requirements from the wider organisation and ensure that the companies present on these basics.