Pros and Cons about using "custom" Functions vs the basic set of nodes

[knolleary]

I've just pushed a fix to git that restores the performance of the Switch node:

Number of messages	Function Time (ms)	Switch Time (ms)
16384	1216	331
32768	2081	600
65536	4125	1124
131072	8282	2207

This fix only applies if the node doesn't try to access context.

I suspect a similar performance regression will have been introduced to the Change node - I'll sort that out next.