We started buying single and multi-family properties for the cash flow.  

I bought a course, but you can do it without buying one.

Don’t the closing costs from buying and selling an investment property eat up all the appreciation (and mortgage principal paydown)?

Crosby as well (from what I have read).Prices are still quite high so you have to buy right and in the right area in order to stay profitable.

So I asked myself, in todays market is it better to fix & flip or buy & hold?

I personally started by buying a cheap crappy duplex.

Yes you can buy properties extremely cheap there but the flipside is that once yoI've rehabbed them, recouping your rehab and purchase money will prove difficult because of the low property values .  

Since you are both finishing programs, I would schedule the next year to be all learning, not trying to buy.

Investment Info:Single-family residence buy & hold investment.

I may be interested in JV'ing on a couple deals depending on what your buy box is and depending on if you plan on being the end buyer or simply wholesaling deals.