I've toyed with this decision a few times in the early days of the project: through-hole components, or surface mount? On the one hand, through-hole components come easier to me, I ﬁnd routing through-hole boards more natural (pure habit), and well, they look more traditional.
On the other hand, and this was the deciding vote, board estate is now precious to me. The PCBs for this project are going to be the biggest cost by far, and the more ICs I can cramp on them the better. With through-hole components, I can place (not route, just place) about 18 ICs on a Eurocard (the register board is indicative — 21 ICs, it took ages to route, and I was very unhappy with it). With SOIC surface mount packages, I estimate I can comfortably ﬁt about 30 ICs on the board and still have space enough for comfortable routing since there are no through-hole pins to steal estate from the bottom layer. And of course, I can also place ICs on the bottom layer. Here's a more complete list of my arguments to myself for switching to SMD:
- Hand-soldering isn't that diﬃcult after all.
- More parts per square unit.
- Ability to use both sides of the board for placing.
- Makes the board easier to route since ICs don't touch both layers.
- Easier availability of surface-mount ICs.
- Many ICs are cheaper in SOIC packages than DIP packages, especially in volume.
- Tiny passive components can be placed pretty much anywhere.
- With the extra board estate, I can include features I couldn't include before.
As an experiment, I re-did the Front Panel Controller board with SOIC and 0805 passive components and the advantages were evident. And since all the boards need a lot of work for the post-front panel layout, I might as well rework them in SMD.