Do I really need dedicated? (Will a good VPS/Semi-dedicated do?)
 

I have been running a vBulletin forum for close to 8 years. For about half that time, I have been on a dedicated server, and to be quite honest, I hate the server management side and am not at all good at keeping things up to date. By reading online tutorials I have been able to secure the server well enough not to have been hacked during that time, but that's about the only positive thing I can say about my server admin abilities. I don't mind management of my own domain, vBulletin configuration and upgrades and the like, I just hate keeping the underlying server/security up to date, and I don't have the time or desire do learn to do it well.

Current hardware at The Planet:
Pentium 4 2.8 GHz processor and 1 GB RAM, 80 GB hard drive

members: 16,000+ (the vast majority in the US)
avg concurrent users: usually 150-200 during business hours
database size: approx. 1 GB
monthly bandwidth: approx. 60-70 GB (including the non-vbulletin portion of the Web site)
budget - $200/mo max, preferably $150 or less, managed or semi-managed a HUGE plus. There are other parts of the Web site that are not vBulletin focused, but nothing fancy there that requires any unusual specs.

Our current setup has served us pretty well for several years, but I'd like to switch to new hardware before the current hardware bites the dust and I wanted to look around at my options.

I had thought that dedicated was my only option given our forum size, and fully managed dedicated is probably not in my budget (unless I'm not looking at the right hosts--suggestions welcome). However, all the recommendations for URLJet that I have seen here made me explore their hosting options, and they have recommended their semi-dedicated plan to me. They say that because their servers are optimized for vBulletin (mysql/OS tweaked for vBulletin, Intel xeon processors with 8 or 16 cores/RAID-10 storage with 15K RPM Drives, etc, minimum of 12GB error correcting memory) that their semi-dedicated plans can handle vBulletins with 300+ concurrent users w/ ease. Now if that is true, that would give me room for growth and better performance, and a managed server at a price I'm willing to pay. Their highest VPS plan is also an option for me, but URLJet says I'll get better performance and be able to utilize more resources on semi-dedicated than on VPS, and I don't need full root access, just SSH.

Is it too good to be true? Anyone here using URLJet's high end VPS or semi-dedicated plans with forums of similar size to mine? Any other similar high end VPS or semi-dedicated plans/hosts I should consider, particularly if they have servers optimized to run vBulletin? I guess I'm just trying to figure out if having servers optimized for vBulletin makes enough of a difference that I could consider moving from dedicated to semi-dedicated or VPS and rid myself of server management duties.

Thanks in advance for any and all input.