Rather than trying to pinpoint a particular system (I'm partial to Toshiba) - why not try to pinpoint a *good* telecommunications company in your area - one that's been around for a long time, and is likely to be around much longer.
You'd be better off with a mediocre system that is well supported by excellent techs than the best phone system that the techs don't know how to program and support correctly.
Personal recommendations from companies in your area that have had new phone systems installed will be far more valuable than the biased opinions of techs... (in my biased opinion!)
Also, look for a phone system that *can* be integrated with VOIP phones, and Voicemail to Email applications - you might not need it now, but if the system you purchase *has* these capabilities, you are probably buying a relatively newer system...
And, switch to a PRI - you'll have a few advantages there... Caller ID being one of them. But any decent phone system will handle T1 *or* PRI.
As for cost - you can get these cheapy 'Made in Hong Kong' phone systems that are incredibly cheap, but no-one else can program. I recently replaced one of these type systems ... the company had bought it less than a year ago... multiple problems... spend the money for a well known and established phone system - it's cost a tad more upfront - but you'll amortize the cost over 15-20 years or more.
