QUOTE(limhongwoon @ Sep 9 2010, 12:13 PM)
What is the difference between Swiftech MCP-655-B with Tach Sensor and the Switch MCP-355 ? Why Swiftech MCP-355 more expensive ?
MCP-655-B is bigger in size, higher flow rate, more reliable and lasts longer, silent.
MCP-355 is more compact, higher head pressure, noisier, fails faster (going by the RMA rate).
The Laing D5's (MCP-655/655-B) are more popular unless you want everything compact which you will then want to go for MCP-355. I know that certain inexperienced people would give you the wrong information (from pumps to tubings) and I have customers complaining buying the wrong thing based on their wrong recommendation

Hence, make sure you do proper research by referring to reliable forums like
http://www.xtremesystems.org/forums