The downside is that variable policies have the most risk. Think about it, your policy depends on the performance of a mutual fund you pick. As the risk of losing the insurance benefit increases, the premiums will usually drop. In permanent coverage, whole life is the safest, so it's premiums are the usually the highest. Variable life is the riskiest, so its premiums are usually the lowest.
Universal life is in the middle for risk and cost.
The type of insurance you choose depends on your particular circumstances and your risk tolerance. And don't keep putting off buying life insurance. The cost of insurance gets more expensive as you get older and as health deteriorates. Although it may be tough paying the premiums, insurance is one of those things that is better to have and not need, than need and not have. Buying insurance policies for your children or grandchildren is growing in popularity.