Personally, I like the flexibility of a 30 year.

I can meet after 5PM weekdays and more flexibility during weekends

@David Glascock, yes you have a lot of flexibility to operate under in your 1031 exchange. 

One of the nice things about seller financing is that sellers and buyers have broad flexibility in creating a win-win.Many seller financing sales use 5-10 year balloons so if your friend, the seller, wants a structure where he gets paid off in a time frame less than 30yrs, you certainly have the option to buy it with a balloon loan from the seller and than sell it with a baloon loan to a buyer.   

Do tenancy-at-will agreements allow tenants more flexibility in what they do while they live in the building?

Financing terms are very flexible in these commercial loans, and everything is negotiable. 

Plus...escape velocity...Episode 113 – Jay Papasan - Very practical slow and steady adviceEpisode 221 - Tim Shiner - his concept of equity build up and "shearing the sheep" shows some of the flexibility of real estate vs a 401k Last but not least, I also recommend all the tax advice given by my fellow CPAs on the BP Podcast.

Also, it will free up the monthly obligations that come along with it that make life very flexible in the long run. 

Will provide a lot flexibility into the future. 

But because they are tax free and flexible and work great with real estate, I like them better than IRAs and 401ks.