I've been doing some testing on a rather large contrived table (3.65 million rows, populated 1 row at a time for a simulated hour for 1,000 rows, for 10 hours each simulated day, for 365 days with an average row size of 123 bytes) using the worst clustered index key possible and I'm here to tell you that using REORGANIZE is only a bit better than doing no defragmentation at all. The good part about doing no defragmentation is that it builds what I call a "Natural Fill Factor" to actually decrease the number of page splits over time.
To make a much longer story shorter, I've not rebuilt any indexes since 17 Jan 2016 (almost 2 years) on our production boxes. Performance actually got better during the 3 months and has not degraded since. There was one table that grew to a quarter Terabyte and was half empty. It turned out to be the only table they did deletes from. I rebuilt it without growing the MDF file by creating a temporary file group and rebuilding the index to that and then back to the MDF. Since I temporarily move the DB to the Bulk Logged Recovery Model, it was all minimally logged, as well.
There are some other tables that have a bit more space in them (slightly less than 70% page full) but they only amount to 40GB. I say "only" because that's only 4% of a Terabyte database. Everything else is running hot, straight, and normal as if I had carefully planned Fill Factors for every index and rebuilt them just as they were starting to do page splits.
Speaking of page splits, the testing I'm doing on the contrived table shows a nice gentle slope of mostly normal page splits that you would see when an "end page" got full except most of them are mid table because of the GUID. In contrast, if you wait to do a rebuild at 30% fragmentation and rebuild to 70% Fill Factor, you end up with a couple of days of a huge number of page splits. If you have a non-ever-increasing index key and you make the mistake of ever rebuilding that index with a Fill Factor of 100, you get massive amounts of page splits immediately after you rebuild the index. And, like I said, a REORGANIZE isn't much more effective at controlling page splits than doing no index maintenance at all.