It would not be appropriate at this point to choose a winner from two entirely different products. Instead, we shall once again focus on the specific benefits of the two controllers.
Adaptec scored points with its compact construction, low price, low processor load and high utility performance (with the exception of RAID 0/1). The 2110S had some points deducted due to the fact that is is only upgradeable to a limited degree, as the cache memory is soldered to the circuit board.
With the MegaRAID Elite 1650, LSI offers a higher level of RAID. Thanks to two channels, up to 30 drives can be connected. Furthermore, the Elite 1650 also supports exotic RAID modes such as 3/0 and 5/0, for instance. The fact that it is equipped with DIM modules used as cache memory is also a benefit. In addition, the performance is very good in all benchmarks. LSI was able to set itself apart from Adaptec especially with regard to rebuilding.
Even if the rebuild passed off quicker with LSI than with Adaptec, neither module taxes the systems processor during this procedure. Therefore, as long as no excessive data transfers are required, a server would be able to continue operation uninterrupted following the failure of a hard drive and its replacement with a functional specimen.
Meanwhile, priced at $450 (Adaptec) and $700 (LSI), neither controller can be considered a bargain. Adaptec should fulfil basic needs at smaller costs, while LSI offers better performance in exchange for a premium price. But then again, they are not intended for domestic use. You can therefore rest assured that in the server segment you have made a wise investment and that your priceless data stock is safe. The prerequisite for this is, however, the right environment. After all, a system can only be considered secure if all other links in the chain (hardware and software) function equally reliably.