There is no short cut to choosing what is suitable, because whatever you decide there is always a chance there is something far better or worse on peoples preferences and required specifications. The same applies to maintenance contracts and warranties, and all to often you will hear of someone's misfortunes, while other might praise silently.
Having said that, then perhaps look no further than Dell for a business deal, because their products and service seem to cater more for business outlets like some of the major institutions. And through their on-line system, you can choose components on your own specifications and finance limits. but be warned here, because some of Dell parts might be 'modified' to suit Dell only. This use to also apply to the likes of re-badged Dell printer's.
At one point I use to deal with Dell on a fair scale, having had access to various discounts and special deals, but alas that all came to an end, when Dell sales would not honour one of their discount agreements, even though they tried very hard to make the sale, offering other supposed incentives. But I suppose that is life, whatever you choose in the end?.
With regards to PCA reviews, they only review computer's that are supplied to them, usually on perhaps short term loan. Or at least that was the procedures previously.