TTimer vs sleep fro win32 service applicatian?

what are possible pro's and con's for each of this solution?

Personally I recommend TTimer ... sleep can cause the service to hang.

I agree too.. Use TTimer.

Maybe, that TTIme is better, however I am a bit confused in which thread its omExecute handler run?

ServiceThread

procedure Delay(Milliseconds: Int64);
var
Tick: DWord;
Event: THandle;
s: Int64;
begin
Event := CreateEvent(nil, False, False, nil);
try
Tick := GetTickCount + DWord(Milliseconds);
while (Milliseconds > 0) and
(MsgWaitForMultipleObjects(1, Event, False, Milliseconds, QS_ALLINPUT) <>
WAIT_TIMEOUT) do
begin
Application.ProcessMessages;
s := GetTickCount;
Milliseconds := Tick - s;
end;
finally
CloseHandle(Event);
end;
end;