I have a TP Tools 780-TL. I have had it for many years. It does leak a little, but not much. When I first got it, before I ever used it, I used a couple tubes of seam sealer to seal it up as tight as I could. I also added a 2nd light, that made a big difference.
Spend the extra money when you buy a cabinet and get a carbide nozzle. I know they are expensive, but mine has lasted for years. It comes with a ceramic nozzle, and they wear out very quickly.
I had a 20 year old Devilbis 5 hp, single stage, 60 gallon compressor when I got the cabinet, and it lasted about another 3 years before throwing a rod! I replaced it with a much higher quality Quincy 5 hp single stage, 60 gallon with a cast iron, Made in the USA pump. It is enough for what I do, but if you are planning to do a lot of blasting, I would go 2 stage. You can never have too much air volume!
Whatever you do, do NOT use SAND! It will kill you slowly. I like Skat Magic, which is a type of crushed glass . I like it as it cleans faster than glass bead, and leaves a nice finish ready for paint.
As for a dust collector, I just use a 20 gallon shop vac with a good filter, which I clean often. One of these days I will invest in a real cabinet vacuum, as I think it will save material in the long run.
One more thing, wear hearing protection. Between the compressor and the vac, it is loud.