Yes- everyone knows that shared hosting has it's limitations. But 5-20 users in my estimate is to low - you may be more forgiving.
I did have a great email exchange with HostForWeb. Here is the summary from those emails..
Shared Hosting should handle about: 50-100 concurrent users
VPS Hosting should handle about 100-500 concurrent users
Cloud Hosting should handle about 200-800 concurrent users
They could not give estimate on Dedicated Server as it has to many variables.
As HostForWeb says: These are just rough estimates.
So far support has been on par with most other web hosts for the price you pay. I think the Cloud Hosting is a great deal if it does all it says.
It looks like the best and most typical option is 3 steps:
Step 1: Use the shared hosting until you get your Dolphin site developed and as many Boonex bugs and errors squashed and use a few dummy accounts to check everything out. You will get several spammers during this time to help you see how many resources are used. Use their crap to test your site - then toss the trolls out and move on to the next step.
Step 2: Upgrade to the Starter Cloud Hosting(around $50 per month) until you have 1000 or more REAL users.
Step 3: Hopefully you understand capitalism and have made a few bucks on your site by then and can afford the Cloud Hosting upgrades you need to continue to grow your website and put money in the bank.