Depends on the person.
I have had 2 paramedics that I have told not to do it, because I could tell they did not have the drive to do it on their own. They needed deadlines and a set program. They went to B&M schools
I had one paramedic I worked with that I cautioned against it because I knew of the struggles he had just getting his paramedic (he was not a good test taker). He went to Excelsior, failed a few courses (2 of the lifespan courses, one of the FCCA classes), but passed his CPNE the first try (after an 11 month wait). He now is still trying to pass his NCLEX (3rd try next week).
I have 2 others that I encouraged to do it, one did and passed, the other decided on a B&M school (is finishing up in December).
If I don't know them well, I tell them that there are disadvantages of it, as well as advantages. I do not outright say yes or no.
Overall, I would say it is not an option for most. Some think it is an "easy" way to get their RN, some realize before they enroll, others do not.
It took me almost 8 years from the time I took my first pre-req course till I passed the CPNE (end of 2005 to mid 2013). In that time I had 2 job changes, the birth of a child, father diagnosed and passed from cancer, failed a few tests, and all other types of life events.
It was the right choice for me, but it is not for everyone.