I don't like being the first kid on the block with any new technology. I've seen many people get burned. Two years ago there were too many issues with 18F's altogether. Corporate Management was pushing me on getting a lead time to market of sub-one month and the slightest chance of products not working was not an option.

Today, the Compilers and Assemblers work as they should, I have a thousand pieces of varous types working in the field without fault and am pretty happy all round. For example, I've replaced a 16F876, 24LC32 and Resonator with a single 18F2420 (without changing the PCB at all), and in process saved inventory, speeded up manufacture and significantly improved profitability of a popular board. No complaints.

I've not needed the capacity of a 18F2620, I have none actually in the field as yet so I can't comment on it. 18F2420 and 2520... no issues. I'm certainly not going to avoid the part if I need it.

Personally I think many problems are down to user application design flaws, poor PCB layout, or just picking the wrong part for the job.