Differences between Enterprise internet connections with the same nominal bandwidth

Question

First of all, I am new to the forum and am unsure whether this is the right place to post my question. If this is not the right place, I would appreciate you letting me know the best website to ask this question. I am a business person seeking the advice of those who know way more about this stuff than I ever will. I am grateful for any assistance you can provide.

I'm starting a startup accelerator and trying to spec and purchase sufficient bandwidth for a new facility. I have quotes from two different providers at different levels of bandwidth but the prices are wildly different. For example, one is providing 150Mbps bandwidth for $1100/Mo. The other is providing 150Mbps for $250/mo. There must be some profound reason why one is 4x the price.

I'm talking to each of the company representatives and asking them directly about this disparity, but - given that these people are selling - it would be useful to know from an independent source.:

1. what's the likely difference between the two offerings?
2. when is 150Mbps not equal to 150Mbps? i.e. is there likely to be a real difference in the end user experience with vendor A's 150Mbps vs. vendor B's 150Mbps? If so, why?
3. what questions would you be asking these vendors if you were in the market to buy new bandwidth?

Both are fiber connections to the space. The space is in a multi-tenant building.

Answer 1

A few things you should look at:

• is the bandwidth symmetrical? I.E. do you get 150Mbps download AND 150Mbps upload?

• is the bandwidth guaranteed?

• what are the S.L.A. (Service Level Agreement)? In case of SLA breach (that WILL happen), what do you get? What are their support processes?

• What are the size and reputation of both ISP? In case they are not major ISP, how many transit providers do they have?
  (not saying that a bigger ISP is better, sometime a smaller one will offer better price for the same services)

• do you get public IP address (IPv4 and IPv6) with the connection? How many (for IPv4)?

• since this is a multi tenant building, do you share the connection with other tenants, or do you have a dedicated fiber?

Edit to add:

• do they offer associated services, like protection form DDOS attack (uncommon), usage reporting (graphs)...