Four fast-growing mid-size company CEOs shared success drivers at the recent Milwaukee Biz-Tech Conference-Expo. With rapid growth rates and distinctive business models, their advice is worth heeding. The panelists Mary Isbister, President of GenMet, a custom metal fabricator Mike Malatesta, founder and president of Advanced Waste Services, Inc. a customized service provider that reduces customers’ risks and waste. Sue Marks, founder and CEO of Pinstripe, Inc. a talent sourcing solution Craig Schiefelbein, president and CEO of PDS. PDS architects, supplies and implements IT solutions for mid-size companies.  (See my PDS blog.) Their advice Never waste a downturn. Pinstripe invested in self-service infrastructure during the downturn that will speed throughput of candidates and allow its employees to do more work and higher-level work as the economy recovers. According to Harvard Business Review, market shares shift significantly during a downturn, a lesson Pinstripe capitalized upon….