Shared hosting is fine when you are starting out — it is cheap and simple. But as traffic grows, sharing a server with hundreds of other sites leads to slow pages and occasional downtime.
A VPS or cloud setup gives you dedicated resources, better performance and room to scale. It costs more, but for a store or a busy lead-generating site, the reliability pays for itself.
The right answer depends on your traffic and what you run. The goal is simple: infrastructure that is an asset, not a liability.