GG -- this is a great topic -- I know you will receive a lot of good feedback.
I have 3 sons, two of which played college baseball (one is still in HS) -- the oldest played at a Texas D3 and the middle son played at a Texas D1 JUCO. For us, both were good fits from a baseball perspective. Without gory details, I'll make a few general comments and let others pipe in.......as a disclaimer, I assume you are looking in Texas (hence the post here) -- I can only speak for the Texas schools.
-the D2 and D3 programs are very competitive -- the D3 my son attended in Abilene treated their student athletes with a lot of respect and ran the program with class. Without the budget, they approached things like a D1 program
-the competition at the JUCO level is outstanding -- my son saw more 90+ pitchers than we thought existed
From an academic standpoint, it was our experience that the JUCO was an "extension" of high school and some miss the boat when it comes to preparing kids to finish at a 4-year school. Obviously, there are many factors involved, especially the student's motivation, teacher's expectations, etc. My son is a good student and pulled good grades at the JUCO, but it's easy to slide by and become a little complacent when it comes to the school part. He had an adjustment when it came to taking JR/SR level courses at the Big 12 school where he is today.
I think the JUCO coaches target the best athletes they can find (another obvious remark), but let's face it, they have an adventage when it comes to admissions & scholarships. Also, if the kid is a pro prospect -- which my kids weren't -- they can offer the opportunity to be drafted/redrafted on a yearly basis.
Concerning the Texas JUCOS specifically, there are "pipelines", as there are in AZ, that may be attractive to kids that target a specific D1, despite not being ready (academically or athletically) as a freshman.
When is the best time to commit? It depends on the player's goals and his range of choices. Some commit to more than one school -- an NCAA university and a high-level JUCO -- waiting until after the MLB draft to finalize their choice.
-PD