shared servers are notoriously poor/slow compared to dedicated servers or vps... you get what you pay for... really depends on the traffic you get... not much, and wp and sp will be fine...
to handle large images and such you would want a server with more memory... shared hosts wont even get a true memory allocation...
SP works the same whether shared or dedicated or vps... obviously, the more resources you have, the better, php, mysql, apache, wp, sp, etc will work... of course, you can have too much too if not using it...
When I started making my forum I had a few thinks in mind.
#1 The over all vision of the site
#2 Nice clean contemporary design
#3 Customizable, scalable forum
#4 Backups- Automated and manual
#5 Dedicated or shared server (optional for a new site I suppose)
But like you said, you get what you pay!
I'm just trying to figure out the best way to give my site the best chances of succeeding. I just want to make sure I do my due diligents to leave nothing out. That way if it does fail which it won't! I can at least say I gave it the best chance to succeed.
Would you say SP is scalable into the 100,000 rang or higher?
One thing I am good at is getting traffic so I am very confident that will not be the issue. I just want to make sure I cover the basics before I launch my site.
It sounds like you have thought things out pretty well. There are a lot of very busy sites using Simple:Press. I wouldn't worry about it being able to 'Handle the load'.
100,000 what??? We have at least one user that has a 1 million users
and multi-million posts... our biggest user has told he gets hundreds
maybe even a couple thousand of users online at one time... so sp, just
like wp, scales fine... but the system resources have to scale too...
obviously, a wp site with sp will require more resources than just
wp... not uncommon for use to get multi hundred users online at once
(max has been 444) though that number is smaller now with memberships...
I'm running SimplePress on a VPS account from Media Temple. My site has 60k+ users, around 1000-1500 active per day. I've only just started to use Simple Press, so far so good. I pay $50/mo for my plan and it's been great. We'll see if I need an upgrade once people start flooding the forum more.