It's easy to get distracted with mobile protocol (HSDPA vs. EVDO) or "generational" system (GSM-3G vs. EDGE) speed claims. In fact, that's the most common conversation that mobile operators, hardware manufacturers, and customers have.
But it's only a piece of the puzzle. The other big ones include latency (the time required to establish a connection and get the packets flowing) and congestion (the instantaneous demand for bandwidth relative to the current capacity in a location).
Not to downplay the value of 3G+ data speeds, it is still instructive how well a "slow" connection can work when congestion is low, and how badly 3G can work when congestion is high.
Apple iPhone customers have complained about the high congestion experience. The other day I had an interesting low congestion experience.
I was in a corner of San Rafael where my phone could only negotiate GPRS -- but I had the air to myself. Subjectively, the browsing experience was better than a typical EDGE connection on the same hardware, and similar (for modest amounts of data) to the 3G experience.
Demand on the network changes constantly as users do different things, and the effective capacity changes due to everything from weather to RF interference to upstream network congestion. So it's not easy for an operator to make a priori statements about actual speeds or actual congestion ... hence they talk about the protocols they offer and their "optimal throughput."
But congestion/capacity issues are a first-order concern in many areas, so I propose some mechanism be created so that customers and operators can have an informed negotiation about service.
I'd like to see a coverage map, for example, that doesn't just show "3G" areas in a certain color -- but also color codes the average real utilization over the past 90 days. Sort of like shopping for an airline ticket and looking at that column that shows "on-time percentage." It lets a customer separate the hypothetical performance from what can actually be expected.
That information would also motivate operators to invest in capacity and infrastructure where the demand is, rather than trying to extend that "patch of orange" on their coverage map to one more town for sales purposes.