Exclusive access allows lower latency, but restricts all other applications from using the device at the same time. Requires at least Windows Vista Update 1. One major advantage of Exclusive over Shared mode is that all and any processing other than audio hardware is disabled. This includes various noise suppression filters, audio playback enhancements, surround mode filters etc.. You get only pure orignal audio. The other reason is the possibility for lower latency. 

The drawback is that the appropriate latency, which will work well, needs to be selected by the user. Large enough latency only increases the chance, that there will be no skipping, but this possibility is never completely eliminated. Typically a safe value is around 20ms for an internal audio board and around 50ms for a USB board. USB audio cards from Creative Labs require as much as 100ms latency for pop and click clear audio. It is possible sometimes to go as low as 5ms or 3ms, but this heavily depends upon audio hardware and the provided drivers. If latency is not a big requirement, it is recommended to stay well in the safe region. (Internal Audio card 40ms and USB Sound card 100ms). 

We noticed that TSaveDialog or TOpenDialog will cause a glitch in playback when opening for latencies below 20ms, regardless of how high the playback thread priority is set. 

Testing the audio at a given latency can be quite an involved procedure, because errors (tiny clicks and pops) occuring every few seconds can be quite difficult to hear without proper equipment. These errors might only be happening when a certain type of computing load is put either on the application itself or some other program. If you are after the most reliable recording and playback possible, then using ASIO 2.0 via TSignalAsio would be a better choice. (Provided of course, that driver support is available.) 

State of things in 2017 on Windows 8.1 with RealTek and Create Labs hardware. 

Note: Changing value from false to true or vice versa will refresh the list of available devices and set DeviceIndex to -1 (default playback/recording device).

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