I was a little surprised in finding the answer to this question, from a Catholic perspective at least, kind of reversed the tradition of parishes representing a contiguous geographical area.
One of the precepts of the Catholic Church is to
provide for the needs of the church, the church being the universal church, the diocese and the local parish where one is a member. I don't have the old canon reference for it, but anyone over 50 will tell you that one is "not really supposed to a parish across town".
But, if this were true, it would still say this in canon law, and it doesn't.
This, is what canon law says about the laity's obligation concerning Mass
Can. 1247 On Sundays and other holy days of obligation, the faithful are obliged to participate in the Mass.
Now, you're talking about homilies and sermons, other preaching and teaching is certainly up to you to find, but homilies and sermons would only be in the context of a greater form of worship and are definitely special creatures.
But, they're not the most important part. I don't know what the most important part of a protestant service is, but the most important part of the Catholic Mass is in the Liturgy of the Eucharist, not the Liturgy of the Word (which the homily is a part of) and that part, unless some profoundly illicit thing is happening, should have equal awesomeness wherever you go.
That being said a common complaint of apostates and other sorry folks is that, "they're not being fed" when they go to Mass. Well, in truth, unless they're avoiding communion, which I doubt, they are being fed. The problem is that they feel the preaching isn't reaching them. But, that's what G.K. Chesterton and C.S. Lewis are for and those guys aren't even priests the priest has to talk about the scripture or some part of the Mass, he can't go off on a tangent every week about the horrors of pornography.
So, before I go off on a tangent and write more than you want to read :), the best advice I can give is to go to Mass early and pray and occasionally go to a church where you know the preaching is on fire, but make sure you provide for the needs of your local church because they probably provide a lot of important services, besides preaching, which is vitally important to the needs of your, more immediate, community.