Ross Muken, ISI Group

FORTUNE — The Bear: Ross Muken, ISI Group. It’s been a challenging period for Life Technologies LIFE over the past two years, and it could get worse. Life has had a core advantage in global government and academic research funding, which accounts for 35% of revenue. But given the fiscal disarray in developed markets, academic R&D budgets could enter a prolonged period of decline. Life is a great cash-flow machine, but its use of that cash has been flawed. In 2010 the company paid too much to buy Ion Torrent, which sells an inexpensive DNA sequencer that could lose out to technology from rival Illumina ILMN . All this will lead to an estimated 1% drop in cash from operations by the end of its fiscal year, vs. 2011. There’s a lot of value in the company, but management hasn’t told us how it’s going to fix the problems.

15 top stock picks from star investors

Amanda Murphy, William Blair & Co.

The bull: Amanda Murphy, William Blair & Co. The company is pretty large and diverse. It focuses more on selling instruments to run large machines in a lab as opposed to the machines themselves. This creates a recurring, stable revenue stream with great margins and lots of cash. It also minimizes the exposure to academic budget cuts, since instruments won’t suffer as much as higher-priced products. Some criticized the price they paid for Ion Torrent. But it gave Life a fresh product line, though there’s some angst around the competition. Still, sequencing is a relatively small part of the $3.8 billion company. This is really a value stock trading at 12.5 times 2013 earnings per share. And, with a robust cash flow that we expect to jump 25% next year, it’s arguably cheap.

This story is from the February 4, 2013 issue of Fortune.