First of all, i have to say that I have been very pleased with both Ultimarc and GroovyGameGear....and LizardLick as well. when i was building my 2 player panel a year or so ago, i ordered stuff from both Ultimarc and GroovyGameGear, and i am very pleased with their products. I absolutely love my u360s and Utrak, however the Utrak's USB interface didn't support mouse buttons, so i went elsewhere and bought an optiwiz, which i absolutely love. I got my happ buttons from GGG as well, and a few novagems (awesome).
i had a problem with one of my u360s (my fault) and my utrak (bad optic board) and Andy's customer service was above and beyond anything i have ever experienced. i didn't have any problems with my GGG stuff, so i dont know how their customer support is. Ultimarc takes it here on shipping though, as i placed my order on the same day, and received my ultimarc order 3 days before my GGG order.
when i was working on my DK cabinet, i ordered a JLW and some buttons from lizardlick, i was very impressed with how quickly i received my stuff.
Currently, i am starting on a 4 player cabinet and i recently placed two orders for components, one from GGG and one from lizardlick. I bought the keywiz, and a bunch of happ buttons from GGG, and some Sanwa JLWs and black start buttons from lizardlick. I ordered them Wednesday evening, my lizardlick order arrived Saturday via USPS, however as far as I can tell, my GGG order hasnt shipped yet. Maybe they just didnt send me an email telling me it shipped, but either way, they take 2nd place in terms of shipping.
I'm looking forward to trying the keywiz, i am currently using my u360s for a button interface, and i have used an ipac4 in the cabinet at work. i'm sure it will work just fine.
I don't have any complaints about ultimarc, i like their products alot, and their customer service is second to none. I've had a few problems, but Andy always answers emails quickly and replaces anything that needs replaced very quickly.
I have no complaints about lizardlick either, they have a great selection of components and they ship quickly.
the only complaint i have about groovygamegear is that it takes longer to get your stuff than it does from other sources (even sources from other countries). It is nothing excessive, but waiting a few days longer for parts sucks. however they have great prices on happ buttons and some cool custom parts you can't get anywhere else.
i have also ordered from divemaster a long time ago when we built our cab at work, he has a great selection of products and great prices. at that time i dont think he had a website, but i placed an order using the B/S/T forum. it took longer than i would have liked to get the stuff, but it is understandable considering he does this in his spare time. i think it was about 10 days from the time i ordered till i got my stuff, which still isnt bad.
bottom line, we are very fortunate that we have several great venders that cater to our niche market. Both Randy and Andy have created custom products specifically for our use, and we are very fortunate that we have such a great support system for our hobby.