Hi,Jim

You're absolutely right ...

But, the 16F628A ( 2K memory) is the best feature/cost ratio ... cause widely diffused.
the 16F648 is the same w/ 4K memory
the 16F88 is one of the most powerful ( forgotten the 18F1320 ??? ),but costs a bit more.

Those are all 18 pins devices ...

Now you understand the pincount is another thing to look at ...

The 16F84 ??? ha,ha,ha ... it was the FIRST one with Electrically reprogrammable memory ( consider the 16C84, now out of the market was "THE REAL FIRST").
Lots of people have learned with the '84s and do not update their projects, may be also, like me, they have dozens left in their drawers.

Thats why you still hear about the 16F84 ... no more !!!



To answer your question, 16F84 programs can easily be modified to 16F628,648,or 88 ... which are now strong and bugless values.

With the help of PbP, the programs can really easily be transferred to 18F series ...

Just buy the PIC you can find ( humour !!! ), that fits your mini requirements, and ... do not cost too much !!!

Note "too much" ... is your own advice !!!

Alain