Tell me if there is any problem with the following methods of running conduit to a dry type transformer.

Transformer is sitting on a concrete floor. The primary and secondary conduits are brought directly up into the bottom of the transformer using the proper box connector.

Same situation but stubbing PVC in to the bottom of the transformer with no connector.

Transformer is sitting on floor or hung. A small section of trough or a properly sized pull box is mounted to the side of the transformer where the conductors enter the transformer via chase nipples. The primary and secondary conduits are directly connected to the trough or pull box with no flex. (I know flex is not required)

We were discussing these methods at work today and I'm not sure if there is anything wrong with any of the above methods or not.

They all seem OK although I'm not crazy about stubbing the PVC into the transformer without a connector.

I've always fed the transformer via flex. Just seemed like the easiest way but it can get expensive.

What do you guys think?