I'm interested to see what others experience is but here's my 2 cents:
For background, i'm a complete newbie, 0 deals so far and just started a few weeks ago, but I've been trying to iron out a repeatable system so I've researched all of these.
Propstream: I love it! The company seems to be actively innovating and the platform is easy to use. I've seen others say that there's a learning curve and i definitely agree with that. I think you have to know what "situation" you're targeting and figure out how to best make the filters show that. Other than that ... it has MLS data! They just added a D4$ mobile app around July 2020 -- i think ;) -- which is appealing although i haven't used it yet. It looks comparable to DealMachine but not quite there yet. Because Propstream has both Public Record and MLS data and they seem to actively be pushing updates, they're the front runner for me.
ReiPro: I'm in week 2 of the free trial. The education in that platform has taught me alot although since i haven't had that first deal, i dont exactly know how applicable it is. Seems great though. I doubt i'll continue with it, although i have downloaded all of the free forms they have lol. I mostly signed up for this one because i wanted a system to help me with all the information since i'll be looking to scale eventually and it has a built in step by step process. I dont believe they have MLS data, just public record. They do have a "maid" type service that's supposed to filter out bad SkipTraces & Addresses (i.e. what extra MLS data would have done) but i haven't used it. It's goal is to save u $$ on mailers that dont have to be sent.
Flipster: The marketing around this product is amazing, but I've seen too many bad reviews on bigger pockets over the years to try it. It doesn't have a free trial anymore and i've heard customer service is hard to get a hold of for refunds. I've heard that it only gives you decent stuff at the $300 / month level, which is too steep for me. Everything "looks" great tho other than those horror stories i've heard. I'm interested to see what others think about it from recent use.
All in all, I've pretty much decided to start w/ just propstream and use their D4$ platform since i think they'll continually improve it and that's something i can get behind.