Thanks for the replies guys.
How do South Padre Island and Corpus Christi compare windwise and non kiting activities wise?
We have been in SPI in October. Just for kiteboarding and that's all what you can do here. SPI is just a five mile road with hotel, motels, restaurants and cheap souvenir shops left and right. The funny part is we had to come to TX to have the worst BBQ ever: Big Boys! Six different dishes and they all were garbage. All six of us stopped eating instantly and asked the waiter to clean the table. She was embarrassed, the manger not so much. I sported the bill of $100 (plus a $20 tip for her) without saying anything. Hey, I am on vacation and don't need to pick a fight. A better place was SPI Brewery. The experience with the BBQ is matching pretty much my overall impression of SPI. Nobody really cares and service is ok at best.
Don't go for a vacation rental. We contacted 10+ places beforehand and only got two (!) responses after two weeks. Some voice mail greetings of agents/home owners were still referring to June/July of 2012 ...
In a nutshell: All vacation rentals have a $100 - $150 cleaning fee hidden in their contracts. You also have to leave a security deposit of a weeks rent, which would have been in our case $1200. You also have a LOCAL TAX of 14% if you stay less than 30 days. And one guy even sent me a contract with $300 over the quoted rent. You know, we are Californians and we are perceived as 'having money', but we ain't schtupied.
In the end my choice was the La Quinta hotel at the north end of town. I had a room at ground level at the pool side, so I could easy access ocean. Another advantage is easy handling your gear; just over the balcony. A utility hose was right next to it and I jumped with my gear into the pool to 'rinse off'. Another benefit is, that you can walk to the convention center for a session in the bay. In front of the hotel is a shuttle stop which is transporting you (and you gear) for free if you do a downwinder to the south end of town - easy peasy.
Which brings me to kiting.
The kite community is great. SPI kiteboarding has a nice shop, we bought some gear to keep the economy happy and one member of our group even took a day lesson with one of their instructors. Feedback was absolute positive and she had a great experience.
We tried 10+ bay side spots for kite access. 9 of them are dumpy. Loose barbwire, ponds of broken beer bottles, seas of shell crush, abandoned fireplaces and mud, mud and ... guess what ... mud. We ended up to use the convention center the most. Here you have a grassy area to set up your kite and with a little walk you get into the water. The mud and slick makes it very tricky to launch and walk in higher winds. Unless you don't care about your kite.
I loved the ocean shore. On a good day you have several (mostly four) break lines of nice swell. Between those swell lines you have ~100 feet wide 'ponds' which are almost flat water. Bottom line is with the right wind and swell you have the whole cake and you can eat it too.
For my end, I don't plan to come back to SPI. For the amount of money we spent and what we got I would know 10+ places for a (way) better experience. SPI as a town and place just doesn't cut it for me. Somehow it's missing some 'magic' or - well - Aloha. If you are into cheap booze and 'Nothing-Over-$3.99-Chachkies' this place will be haven for you. Otherwise kite, eat sleep and leave after 14 days ...