To me, transubstantiation is very similar to the act of remembrance deeply affecting a person, in that they both involve internalising Christ, having Christ become part of a person - which involves Christ being made manifest in the physical world. The act of recognising Christ in all creation, means He is made manifest.
Saying that, I appreciate the miracle in receiving Eucharist, as at this point during the act of receiving, Christ's manifestation becomes real and is realised.
What I find difficult is where the Eucharist is valued in terms of being a ritualistic act, that is performed, because to me this seems more aligned with some Pagan beliefs which see power in the performance of ritual acts. But this would, IMO, be an example of not appreciating the true meaning of the Eucharist, which I fully expect would go against Roman Catholic belief too.
I think Church unity between all the body of Christ is important:
Galatians 3:27-29New International Version (NIV)
"27 for all of you who were baptized into Christ have clothed yourselves with Christ. 28 There is neither Jew nor Gentile, neither slave nor free, nor is there male and female, for you are all one in Christ Jesus. 29 If you belong to Christ, then you are Abraham’s seed, and heirs according to the promise."
1 Corinthians 1:9-11New International Version (NIV)
"9 God is faithful, who has called you into fellowship with his Son, Jesus Christ our Lord.
A Church Divided Over Leaders
10 I appeal to you, brothers and sisters,[a] in the name of our Lord Jesus Christ, that all of you agree with one another in what you say and that there be no divisions among you, but that you be perfectly united in mind and thought. 11 My brothers and sisters, some from Chloe’s household have informed me that there are quarrels among you."
..so I think it is important to remember, however we individually understand the mystery of the Eucharist, the end result should be that Christ is in us and we are in Christ.