How do you want suppliers to discuss their performance or impact on your business through their supply chain capabilities with you? Example: Supplier X is looking to schedule a Quarterly Business Review with you, what verbiage or metrics would be most impactful to your company and drive the conversation forward?

Short-term: Quality, Delivery (on time), Cost (total landed)
Long-term: Cost reduction ideas, capacity, supply chain health

When discussing your performance and impact on our business, we value a data-driven approach that focuses on key metrics and outcomes. During the Quarterly Business Review, we expect suppliers to provide clear insights into the following areas:

On-time Delivery
Quality Metrics: Defect rates, product quality, and adherence to specifications.
Cost Efficiency
Communication and Responsiveness
Innovation
Risk Management
Customer Feedback
Environmental and Ethical Practices
Long-term Partnership

Great responses, everyone- any more context and voting will still be valuable at this point to gain understanding.

I appreciate how harsh this sounds, but when it comes to business, very often there is as lot of asymmetry nd doing this may or may not help.

Suppose if you make deposit envelopes for ATMs (I wanted to pick a relatively niche but recognizable industry/item.) Chances are that you may not have many customers and you will have a lot of sales concentration (i.e. most of your sales will go to a handful of customers, i.e. your top 5 customers out of 100 total may account for 80% of your business. Let's say your top customer is JP Morgan. If you try to setup a meeting with JP Morgan, chances are that it won't be with Jamie Diamond. Chances are that if you try to cozy up you may just put a target on your firm (i.e. you'll draw their attention on how much they're spending on envelopes and if there is a better/cheaper supplier out there.) 

You might have them JP Morgan as a strategic business partner but chances are they won't have you as a strategic business partner.

There are times when the relationship is more balanced. In this case you can expect that there might be some rivalry between the two firms. Your customer may want to move into your area or you into theirs. This is less likely (but it can happen) if one firm is much larger than the other.

If you are meeting with your customer, you should have a game plan for what you can do to help. Often you might have an idea but you aren't a large spend for your customer. Their attention may be elsewhere. 

Yes, partnering with them may give you insights into what they're doing and this can be helpful but are you ready to make that type of investment? Are you able to raise your prices as a result or will you just integrate further and will your customer view your investment as a cost of doing business with them?

From the customer's point of view, if they meet with you, engage with you and let you into their strategy, what guarantees do they have that you won't turn around and offer something similar to their competitor and often for less? Speaking from prior experience, I worked a firm and one of the VPs was speaking and said that they had partnered with a Customer, helped them do X for $Y and afterwards realized that for much less they could help another firm ( a competitor) do something similar for less. Who won here? The customer just helped train a supplier who will then increase competitive rivalry in their industry.

Before you go down the partnership route, ask yourself and the other party, what are your goals. Are the goals compatible? Very often firms give lip service to things like partnership, relationships etc. but in the end things come down to price. You need to know the real reasons and then work accordingly.

I'd like to add here that if a supplier wants to schedule a QBR, then it is already a great sign. Usually it is the customer who initiates these reviews (some industries are exceptions though).
In all cases, a structured review and an agreement to what constitutes value and customer business outcome beyond the 3 mentioned are critical to ensure the two companies work well together and it is a two-way street or a win-win.