It depends to a great extent on the level of latinisation present in a Byzantine Catholic parish. In cases where there is lots of latinisation, you might witness strange hybrid liturgical practices that incorporate Western and Eastern elements. Some Eastern Catholic parishes will at times offer their faithful the option of attending "recited" liturgy, a kind of "low mass", if you will, where nothing is chanted and everything simply recited in speaking tones. There are some Byzantine Catholic parishes that have done really well in trying to stick to an authentic Eastern liturgical practice (including a few that are so good at it that they are more "Orthodox" in their practice than some Orthodox parishes; i.e., they have excellent chant, are rubrically very precise etc.). In a parish like this, the only difference you will notice will be the commeration of the Pope here and there in the liturgy. There are also translation preferences that seem to further distinguish the Orthodox and the Byzantine Catholics in North America. For example, it seems that Eastern Catholics have a marked preference for finishing prayers with "now and forever and ever" instead of "now and ever and unto ages of ages." Also, many Catholic parishes will not commemorate important post-schism saints like Gregory Palamas, but some will.