I can vouch for Arizona and Kent's operation - I've stayed-dived there several times and it's a dedicated resort and dive centre for serious divers.
I'm not a Tech diver (yet) but have done plenty of wrecks and deep dives in SB, and have always felt well managed and safe with Arizona's team.
The staff at Arizona resort are also excellent and make the effort to ensure you feel welcome. The food is pretty good with healthy portions - beers are cheap too.
Staying at a resort on the beach with the dive centre there also makes the convenient difference, don't know why you'd stay anywhere else.
Just for accuracy... the beers aren't particularly cheap by Philippines standards...more than double (80php) what I'd pay in some places (35php).... but you expect that with resorts.
Boardwalk has been running tech level diving for a long time, and their support is excellent at all levels. They're very 'DIR' friendly... and have hosted some big 'names' from GUE and UTD etc over the years.
Arizona is less experienced with higher level tech support, but Kent and his team have a wonderful 'can-do' attitude and spare no effort in providing everything a visiting tech diver would need. They are very sidemount friendly - with a large stock of dedicated L/R-handed cylinders and rental Apeks sidemount BCDs and regulator sets.
Arizona is based in a (very popular and well established) western-run resort... so you've got everything you need in one place. The rooms are good value and the food is Australian/American... good steaks... and the Blue Fin sashimi is excellent value at $5.
Boardwalk is a stand-alone dive center, but there's accommodation nearby... a Best Western hotel and some business suite type rooms. There's no food or beverages at Boardwalk.
Arizona is located on Barretto Beach... it's primarily popular with western visitors...more of a 'beach area'. It's also where the main bar nightlife is. There's a range of American, Japanese, British and Filipino restaurants... even a new place doing Middle Eastern cuisine. There's cheap trikes to get around.
Boardwalk is inside SBFZ (the Freeport business area). It's mainly Filipino and Korean hotels and restaurants there... although you can get a good pizza at 'Extremely Xpresso' and awesome food at Texas Joe's. Nightlife is mostly KTV and live music at 'Pier 1', which is a Filipino favorite. It's a 15 min walk to the nice mall at 'Harbor Point', which has McDonald's, Starbucks, TGI Fridays etc.. You have to either walk everywhere or get an (expensive) taxi, as trikes are not allowed to operate inside SBFZ. I wouldn't swim off the beach in SBFZ... unless I really wanted an eye/ear/throat infection.
Boardwalk attracts much of the Chinese/HK/Taiwan market. Arizona is more popular with American/Australian/European tourists.
Boardwalk use a couple of covered speedboat for their dives. The run quick 1-2 dive trips off the beach. They're excellently located for the USS New York, but further from some other sites.
Arizona has probably the best regular dive boat in Subic Bay... the 'Trident 1', which is very spacious and has a large dive deck area. Water entries are great (especially for tech backmount or sidemount) off the ledged pontoon sides. They provide a hot towel post-dive, along with cup noodles or hot coffee and juice. They run 2-dive trips, with 2 boats, that leave punctually at 9am and 2pm every day. For tech divers they'll run bespoke trips.
Staff at both dive centres are excellent, and very safe. Both equip properly with O2 and 1st aid kits. Both supply very clean gas.
