I stayed at JW Bonnet Creek in May 21, I do not remember a lazy river there. We actually found the pool area there to be quite small and the hotel itself while brand new and quite luxurious, has more of a "business" feel. Thats not to say that we did not see children there of course! They did have kid zones and play areas (outside of the pool area) but we did not see many kids using them,(I think they were pay to play) and of course it is close to Springs. Grande Lakes is much more family friendly imho. There is a huge long lazy river, large pool area, all kinds of activities ...golf, tennis, sand volleyball, kayaking, kids activities, wonderful seasonal activities ..(in the past for holiday weekends they have done fireworks shows for example).
The vibe at each is very different...Bonnet Creek has *almost* a Miami-ish feel to it as it is very sleek and modern with lots of concrete, we also heard alot of road noise from I4 since that was what our room overlooked and I believe we were on the 14..? floor, so there I would request a pool view.
Grande Lakes has a more laid back "vacation-y" vibe to it..its tucked away among lush landscaping and really its only about 15 mins to springs from there. Good luck deciding both have great qualities just depends on what you're looking for!