I would say it looks pretty good. I have never made a rail with holes in the top, but i couldn't imagine it being too much of a problem. Also, I haven't really made too many rails with vertical supports, but i have seen many others on here with them, i am sure it will work just fine. If the rail, for some reason isn't as sturdy as you would like it, try triangles like a post a couple posts up. Next time if you want to cut down the cost try and find some left over wood at construction sites or something. But that rail looks pretty sick there, good work.
Coincidentally, I just finished a rail very similar to this one this afternoon. It is twelve feet long with two 1.5 inch pvc pipes. I can't wait to try it out.