The advantage of a Star is speed. The disadvantage is that changing and readjusting sizing dies can be a slow process. So if you can afford to set one up and just leave it AND you need a lot of bullets of one particular type, a Star is nice. I've probably owned six. Now I'm down to one.
If you buy a Star, DO NOT buy the bullet feeder. It is a real pain, costs a fair amount and just slows you down. The heated base, however, is worth the money. Star's, incidentally, are arranged on your workbench so that the bullets must fall through a hole in the top of your workbench.
The SAECO is, well, unfortunate. Currently made SAECO's have a main gasket that is prone to tear. Once that happens the gasket inverts so if you try to put a new one based on the looks of the old one when you took the old one out you are in for a REAL problem. It does not help, incidentally, that the gasket replacement "kit" comes with no drawing and has an extra, completely unnecessary part. This is the only product SAECO makes that I would NOT recommend.
The RCBS can use any RCBS or Lyman sizing die. It is guaranteed forever. Not a minor consideration.
Both the RCBS and Lyman are limited in the size of the maximum bullet that they can easily handle. Roughly around 0.510 inches. Both will accept sizing dies larger than that but getting those dies out can be a real experience.
The Lyman 45 is so old that you are not likely to run across one.
The Lyman 450 was made for some time. It was dropped because it leaks lubricant out the bottom. That problem can not be fixed. Some time during the 450's manufacturing life the tolerances on both the machine and the sizing dies were tightened up considerably. So a REALLY old 450 can use any RCBS or Lyman sizing die. A newer one will not. No way to know which is which.
The 4500 solves the leakage problem but can only handle recently made sizing dies. It can be purchased with or without an integral heater. You can add the heater later. The heater is money well spent.
Currently I have one Star, one Lee, one Lyman 45, one Lyman 450, three Lyman 4500's and two RCBS's. I sold my SAECO (and would not want another) and I sold most of my Star's.