LaserEngineer

They are like the Wal-Mart of industrial parts and supplies. You'll find just about anything, it will be available quickly and cheaply, but you won't always get the highest quality. I haven't needed to call for support, but they are a large distributor so I would assume there is support available.

Strengths: Huge selection across many categories, competitive pricing for low or high quantity, fast shipping, quality is generally good. Terrific website with full part descriptions and easy interface for ordering.

Needs to improve: Quality is not always the best, but you get what you pay for.

Semitec will now be one of my first stops when searching for electronic parts.

Strengths: Great customer service. I was looking to replace an uncommon GE thermistor after a 100x price increase, and found a Semitec part on mouser.com. I emailed Semitec about a modification to extend and insulate the leads, and within a day I received a call from an engineer named Naoshi asking for details and providing spec sheets, lead time estimates, etc. He even sent me samples to test, and they arrived within 2 days. Excellent customer service and technical support.

Needs to improve: The lead time on my custom part is a bit long at 10-12 weeks. I was assured they are working to decrease this, but I may just use the off-the-shelf thermistor rather than order the custom part.