Just had time to study how the Lending market works at Bitfinex: it seems terrible, in my option:

1. They pay less then Polo (3.5% per month at Bitfinex against 5.5% per month on Poloniex)

2. They have a FRR (Flash Return Rate) feature, which is an average value from last hour saying the best rate to make Loans - This is terrible because it creates an influenced market by FRR feature. It's not a free market. The sentence "create a loan for the highest price, get a loan for the cheapest price, the market will close the best deals for both sides" is FALSE because of this FRR feature. If you check this image (http://imgur.com/a/HOnmK) - you will see there's a huge gap between rates, showing the influence of FRR feature. Terrible feature.

3. A Bot could not work in a non-free market like this at Bitfinex, where the price is determined by "an average value of last hour" - but in the last hour the FRR was ruling the market, closing the 95% of the deals, then guess what: the rate will be almost the same, for ever, tending to zero.

FRR is a really bad feature.