I don't know about brands but I'm concerned about your considered pump size. I know that money is always a big part of the choice but UM-----I will never regret getting a bigger pump. OK, for one thing, my waterfall sounds GOOOOOOD because the pump pushes lots of water. For another thing, when my pond starts going green, I can filter it out quickly because it turns over so much so quickly. I put extra pieces of filter media in mesh baskets in the steps of the waterfall. A negative probably is that it costs more to run a bigger pump. I would guess my pond is less that 2,000 gallons and my first pump was a 3200 GPH. This one is 3,000. You'll never regret getting a larger pump but a smaller one,,,maybe.
Another thing to think about is either getting a pump with a float built in or installing a separate one so that if for some reason the water gets pumped out of the pond, you don't ruin your pump, lose all your water, and don't lose your fish. Yes, I know they reccommend the water turnover be every half hour but have had this pond about 8 years and it's clear most of the time and clears quickly when there is a problem. Oh an never put the pump at the bottom of your pond.
Also depth, I love being able to get in my pond and deadhead the done blossoms and yellowing lily pads. Mine is between 24" and 30". It allows me to work in it easily because I am short. My tip is to stand on the kitchen floor and bend over turning your head to the side as far as you can, while reaching down to touch the floor. Have Vicki measure the distance between your nose and the floor. That's how deep to make your pond. You can touch bottom without drowning. Sounds like a joke but "no". If I want to pick something off the bottom of my pond, I can. Another thing, get a regular swimming pool handle and leaf skimmer. You might want to add a layer of toule (tutu net fabric). I say the swimming pool handle because it adjusts waaaaaay out and you will be able to scoop the crud off the bottom from anywhere on the side of your pond, fish things off the bottom without getting in, and reach the whole surface of your pond bottom. The toule is a fine net and catches a lot of the gunk that goes through a regular leaf net.
There's a big controversy about plant ledges. I love my plant ledges. I put the lilies on the ledges when they first start in the spring and then drop some of them down to the bottom later. Also----I made a spot with steps going down in both ponds. I shaped the steps out of wet sand, layed cement patio blocks on the step and back, covered it all with carpet and then layed the liner over it. It is very easy to get in and out for me. Also, when I put the mini fence around the sides, I made sure to put one of the posts right at the side of the step top so I have something to grab and steady myself. But I have had what I think was a heron try to land on one of my pots. It was tipped into the pond. I have a small kind of decorative rope fence around the open sides of my pond with marginals growing up under it. Herons won't climb over or crawl under the fence. They don't like walking through tangly stuff either.
Another thing, don't make the bottom bowl shaped if you can avoid it. I think it is too hard to scoop the bottom and get as much of the leaves and gook off when the sides slant over to the bottom and then the bottom is curved. Also walking in it,,,,if you are planning on it, is nigh impossible when the bottom is gunky, which it usually is,,,, slippery as all get out. Just ask me how I know.
Another thing---lots of another things----buy a liner that is much bigger than you think you'll need. DO NOT CUT off the excess. Roll it down and under in case you need to change something around the edges, you can.
You're lucky there that you don't have to worry about freezing pipes. So run water pipes over close to your pond so you don't have to drag a hose out everytime you want to top off the pond or clean a filter. While you're digging, run your electric lines to more than one spot around the pond. At first, you'll find you want to plug in fountains, spitters, lights and all kinds of interesting electrical things. Most of all, BE SURE TO USE A GFI. Dont' want you frying your fish or yourself. We eventually put a patio alongside the pond so the electricity comes in handy.
Oh and look around before you start digging to find the nearest trees or bushes that drop leaves. Around here, I swear, leaves blow in from neighboring states. Seems that way anyway. There are oak trees up the road. They are tough and thick and don't decompose easily. They blow into the pond the next spring yet. The Maple leaves mat together and don't blow as easily after while.
Does Texas have rocks? Anyway, better start now getting the word around that you need rocks. Put a piece of plastic or rubber roofing in the trunk of your car and a small shovel. Watch along the roadsides and when noone is looking, grab the rocks. I like ones that are around 8"-10" and smaller. I find that after 8 years, I'm still adjusting the placement on them and want my rocks small enough for me to handle them. Stream beds are another place to find rocks. Farmers sometimes have rockpiles as they gather them from the fields to keep the equipment clear of them. And lastly, neighborhood lawns and parks usually have some nice ones.