How does having multiple peers affect an ISPs performance?
If I have 2 option of ISPs to select from, where ISP1 has only 2 peers and ISP2 has 10 peers, which one should I select?
Or does number of peers even matter?
A larger number of peers basically means that the ISP is better connected - more efficient and possibly more redundant.
However, the pure figure doesn't tell you everything. It's also about the quality of those peerings (bandwidth, redundancy, capabilities and size of peer/carrier, ...).