Wow - a blast from the past. That was almost six years ago.
In general, not much has changed since then with respect to me using user defined facts as to do lists and research logs, so I don't have much to add. The only thing I notice that's different between now and six years ago is that since then I have reduced from many different user defined fact types to manage research down to just two - one for to_do lists and one for research_logs. What I am doing or researching is really managed the same whether the underlying data is marriages or burials or births or obituaries or whatever. But I still want to use user defined fact types so that I can search them, sort them, use People View with them, use Custom Reports with them etc. and they are fully integrated in with the rest of my RM data.
There are a couple of other things I have changed since then. One of them uses user defined fact types, but does not use user defined fact types to manage to do lists and research logs. For example, I have a Marriage Record fact type to contain transcripts of courthouse marriage records. In one of my screencasts in this thread, I showed a Marriage fact that included a transcript of the the courthouse marriage record as a Note for the Marriage fact. I mentioned in the screencast that I wasn't sure if this was a good idea or not. So I have split the standard Marriage fact type with my own Marriage Record fact type, with the former not having a transcription of the marriage record and with the latter including a transcription of the marriage record. Therefore I can include the transcription in reports or exclude the transcription from reports by including or excluding the Marriage Record fact type from reports. I do the same sort of thing with births, deaths, and burials - splitting the data into multiple fact types so I can include or exclude transcriptions from reports. The ability that RM has to include or exclude Notes from reports simply isn't flexible enough for my needs. But the same source is used for both the Marriage fact and the Marriage Record fact. The source has a transcription of the record and an image of the record, so all the data is there in any case.
The other thing I have done since then doesn't really involve user defined fact types. Instead, it involves a fairly complex SQLite script I developed to identify certain missing data. Primarily, it identifies facts without sources and sources without multimedia files. You can get facts without sources from RM itself, but the way you can do so is pretty clunky. You can't get sources without multimedia files at all from RM itself. Hence, I needed an SQLite script to provide the information for me, and i integrated all the missing information into the same SQLite script.
It appears from RM8 demos that research logs and to do lists are being integrated with each other. What I can't tell from the RM8 demos so far is whether the integrated research log and do to list feature in RM8 is further integrated into the rest of RM8 so that you can make groups, color code, and otherwise search about research and to do items in RM8.