Bitshares delegates are elected by shareholders, and they are similar to miners. (They create the blocks, and they also supply price feeds that help the system's internal exchange function).
Delegates get paid BTS as a reward, just like bitcoin miners.
Most delegates get a reward of 1.5 BTS each time their turn comes up. Each delegate creates 1 out of 101 blocks, so they get paid 1.5 BTS per 1010 seconds.
A few delegates are "paid delegates", who are people such as developers working for bitshares. They are also elected by shareholders. For example, Toast (Nikolai) was the first person to be elected as a paid delegate.
Paid delegates get 50 BTS instead of 1.5 when they create a block. However, they are performing valuable services for bitshares such as working as a developer. (If they werent, shareholders would not vote them into a paid position).
It is also possible for a delegate to receive partial pay (any amount lower than 50 BTS). The pay level is set when they create the delegate, and then if voters agree, they will get voted in. No delegate can get more than 50 BTS per block.
The maximum possible inflation would occur if voters elected 101 paid delegates at 100% pay rate of the full 50 BTS per block. If this occurred, inflation would be about 6.3%. At the current rate, there are less than 10 full pay delegates, plus about 90 normal delegates that get only 1.5 BTS (3% pay). As a result, inflation is around .7% currently, which is pretty tiny. If we got a lot more paid delegates, inflation would go up, but that would also mean that many people had been hired by bitshares to work as developers, marketers, etc, that voters trusted and chose to vote for, so if we ever have inflation in the range that bitcoin does, it would also mean we have dozens of devs working on the bitshares product.