Though the infantry was the main part of Roman armies, cavalry was also employed, and this subject has been little covered by soldier manufacturers in the past. Though foreign mercenary cavalry was often used, there were also true 'Roman' cavalry units, and it is these men that are depicted in this set.
One glance of the scans and statistics of this set will tell you most of what you need to know here. The two poses are of a man with sword raised and a man with javelin raised. The javelin is a separate piece from the rider, and a ring hand is provided for it. It has not been included in the above scan because it is about twice the necessary thickness to fit into the hand. It is also very short (about two metres instead of the correct length of nearer three) and with an absurdly large head. In short it is a crude piece that is neither accurate nor capable of being inserted into the rider's hand.
The men are no better. They are both semi-flat, being several times wider than they are deep when viewed from above. The arms and also directly above the head, making the figures seem very 2-dimensional and almost disappearing when viewed from the side. They fit very poorly onto the horses and require considerable knife-work to be persuaded to stay mounted. The resulting position is very unnatural. Apart from the weapons the two poses are very similar, and seem to exhibit no life at all.
As you might expect from semi-flats, detail is poorly defined and difficult to see. What there is suggests they are appropriate for the late republican or early imperial period as they wear short mail shirts, with one also wearing the shoulder straps typical of this time. However precise details are very difficult to make out, and this is particularly true of the helmets. Both poses carry a sword, but not the long spatha type that they should possess.
The horses are, if anything, much worse. Roman horses were small, but the beasts in this set tower over their riders. They are also massively overdecorated with elaborate saddles and armour around the body. This is because they are the same horses as are found in the Parthian sets, and they are inappropriate for Roman cavalry in every conceivable way.
This is certainly a strong contender for worst set of plastic soldiers ever made, and anyone wishing to purchase Imperial Roman cavalry would be well advised to wait for the output from other manufacturers or do without. This is no more than a waste of good plastic.
Note that many LW sets seem to have various horses in various proportions, so the horses and pose counts shown here may not always apply.