Hoping to get some advice, I've kinda always wanted to own a PC Engine but only started looking at it more seriously recently and I'm totally overwhelmed. I should probably preface by saying that I'm in the UK and would want access to CD games, RGB output and not to have to use a step down power converter.
Coregrafx/Supergrafx/Super CD/Duo - Honestly don't know anything about any of these or their compatibility, they seem generally more troublesome to find?
Duo R - This seems to be the one mentioned most. From what I can tell it has a system card built-in so I don't need anything extra? Reliability reports say it's more reliable but then I saw a lot of mentions of capacitor problems (and I really don't want to get into re-capping, still can't find anyone in the UK who can re-cap my Mega Drive). There are RGB modded ones on eBay for around the £250 mark (which is quite painful), but then I saw pictures here of their work and... yeah.... I can't even seen to find any non-modded or properly modded ones for less than £300 which is out of my budget.
Original + CD - From what I can tell I would need a base unit, one of the white CD drives, a grey interface thing and an arcade card (which costs a fortune) to play everything? I have to admit this is the option I find most appealing purely on an aesthetic level and it seems way cheaper, but I saw a lot of reports of poor reliability. I don't mind replacing parts if they are easy to deal with, but not replacing capacitors. Also for RGB modding do you mod the base unit, or the interface?
Controllers - I saw some mention about these having different connections, plus there is the whole 2/3/6 button thing, should I just go for 6 to be safe? They seem expensive regardless.
don't think I can answer all your questions..
but for modding the briefcase set up You can RGB mod the pc engine console itself but if you are playing CD games the cd audlio will not play directly through the console only from the interface.
If you want to play with the few NEO GEO ports on the briefcase setup then you will need an Arcade PRO card.
When NEC first released thir CD-Rom Add on it only came with the system card.
Basically the first system card came with 64k of RAM to load up game data
a few years later they released the Super System card and boosted the RAM to 256k.
The ARCADE PRO card is 2Megabytes of RAM plus 256k and only needed for the briefcase set up.
If you decided to go for the DUO /DUO-R/DUO-RX, They all come with built in 256k so do NOT need any super system card.
Because these have 256k of RAM built then you should go for the ARCADE card which is just the 2megabytes of RAM.
There are a very limited number of games that support the Arcade cards.
games that ran on the first system card had the cd-rom logo
games that ran with the super CD-Rom had this logo
Games that ran on any of the ARCADE cards had this logo
The biggest hiccup imo is the way NEC and Hudson Soft implemented their save game data system... it just gives me headaches...
The worst case scenario is when you load a game and it will warn you that their isn't enough BACK-UP RAM for saving data and the game could possibly delete all your save files....
Both the briefcase interface unit and all the Duo's have built in back-up RAM for saving game data but they are seriously limited. You can invest in a Ten No Koe card or Memory 128 but the problem with the Memory 128 is very few games support it. It requires 4 AA batteries which need to be changed around every 6 months. The Ten No Koe card is a lottery as they are powered by a battery.
The battery might be soldered.
http://nonta6913.blog.so-net.ne.jp/2007-09-29
As for the controllers I think the USA ones are not compatible with japanese consoles....
Well I hope I answered some of that correctly. Nothing worse than typing at 1.25am and not wearing your reading glasses...