I'll start this answer by clarifying an absolutely FUNDAMENTAL issue in REI.

I can provide the actual numbers, but think the fundamental question doesn't require the actual numbers..if i'm wrong i will provide the numbers ASAP.

Forget the guru stuff; there are good solid courses and learning opportunities for a fundamentally sound real estate education.

I will tell you, though, the fundamentals are the most important.  

Though I did "house hack" for over a decade, own a rental property, and recently sold some land, I had not focused much on understanding the fundamentals of how to evaluate a great deal. 

@Larry Roberts,In the education I'm associated with, those fundamental classes are $2,000 for 10 classes available on-line 24x7.

Grand Rapids has super strong fundamentals so won't be hit as hard by a market correction and is still very affordable.

There are a lot of good fundamentals: population growth, several stable industries (federal government, universities), one more volatile industry with major possible upsides (oil/gas), and most important for the real estate investor, attractive price rent ratios, especially as compared to larger urban areas.The major thing I've seen that gives me pause is that rents seem like they've been pretty much flat for the past several years, presumably following the oil/gas price crash.

There will be bumps in the market, but San Diego has a lot of good fundamentals. 

Venture funding masks fundamentally poor business models in the industry.