Here's a simple metric to demonstrate why alternatives to cryonics could be preferred:

Suppose we calculate the overall value of living as the quantity of life multiplied by the quality of life. For lack of a better metric, we can rate our quality of life from 1 to 100. Thus one really good year (quality = 100) is equal to 100 really bad years (ql = 1). If you think quality of life is more important, you can use a larger metric, like 1 to 1000. But for our purposes, let's use a scale to 100.

Some transhumanists have calculated that your life expectancy without aging is about 1300 years (because there's still an annual probability that you will die from an accident, homicide, etc.). Conservatively, let's assume that if cryonics and revivification are successful, you can expect to live for another 1000 years. Also, knowing nothing else about the future, your quality of life will be ~50. Thus your total life-index points gained is 50,000. But suppose that the probability that cryonics/revivification will be successful is 1 in 10,000, or .0001. Thus the expected utility points gained is .0001 * 50,000 = 50.

It will cost your $300/year for the rest of your life to gain those expected 50 points. But suppose you could spend that $300 a year on something that is 80% likely to increase your quality of life by 5 points a year (only 5%) for the rest of your life (let's say another 50 years). There are all kinds of things that could do that: vacations, games, lovers, whatever. That's .80 * 5 * 50 = 200 expected utility points.

You're better off spending your money on things that are highly likely to increase your quality of life here and now, then on things that are highly unlikely or unknown to increase your quantity and quality of life in the future.