Has anybody done this type of loan what kind of loan is this and what is the up side and down side to this type of transaction is it a bad idea? 

@Amber Ponte   lots to learn in Tax lien investing the biggest one is its not a guarantee in any way shape or form..

Look at this situation and with a detached perspective, ask yourself if this is truly an opportunity and what the upside and downsides are.

Then see if that upside is worth the potential downside, based on your judgment and knowledge of the market, along with input from anyone you trust..It looks like most of these bigger deals do have thinner margins due to the larger dollar figures..

Honestly that is the down side to longer term tenants I am finding.

We love San Diego but the price of housing and our mortgage payment is by far our biggest expense, so we are searching for a new home-base (maybe somewhere in the greater Denver/Fort Collins/Longmont/Colorado Springs area, maybe Salt Lake area, but we are considering everything still).

I assume your living close to the campus.I'd recommend buying the biggest home you can afford.

One of the biggest mistakes I've seen is from investors that can't respond to the initial costs because of the lack in liquid funds.

The only downside that I saw was that everyone wanted to see both units (no matter which ad they saw and responded to) so showings took forever.

Fire Dept is within 1 mile, Police Dept 1 mile, and the biggest park in the city is literally 30 feet away.