I think anyone who likes Dominion is highly likely to enjoy Race.
It depends a lot on what you like about in Dominion. Even though these two games are often mentioned in the same discussions, it is largely because for a long time they were the two highest-rated card games that also happened to be released roughly the same time (nowadays Android: Netrunner is ahead of them, and 7 Wonders is quite comparable in popularity amongst players in general). The games have very little in common, so I don't see any particular reason to expect Dominion-fans to like RftG any more than any other group of boardgame fans. Both games fit fairly similar occasions, taking roughly as long to play and both being good games only for small groups of people, but this is roughly where the similarities end.
Also BGG stats support this.
The list of games rated high by Dominion fans has RftG only on the 4th page of results (two of the expansions are a bit higher, as expansions usually are, but still not even within top-100). This compares very poorly to the fact that RftG is ranked 24 overall in BGG. The highest positive correlation Dominion has is naturally with its own expansions, but a lot of other games rated by hundreds or thousands of Dominion players are ahead of RftG, including most of the games ranked above RftG in BGG in general. This result suggests that Dominion fans do not like RftG any more than other gamers, but also that they do not hate it either -- it's just another game out there, liked by some and not by some others.
I personally do not like RftG that much. It was good around the time it came out and one of the expansions made it better, but in the end I have no urge to play it as it feels a bit boring and repetitive (whereas Dominion I would still play any time). Compared to Dominion it loses big time in two important things. First, it is way harder for new players, so it cannot be played casually. For expert players, in turn, it reduces too much into a game where you have to pick your strategy based on whichever cards you happened to see during the early game. The game has a lot of powerful combos and strategies just like Dominion has and I can understand how learning those could be interesting for people who like Dominion, but the big difference is that the game does not offer as convenient way of learning these things. In Dominion you see the whole kingdom and can always choose at the beginning of the game a strategy to try out, to learn more about it or any of the individual cards. In RftG you cannot do that, but instead you might end up playing 5-10 games before you get your first chance to even try out some particular strategy you are interested, or 10-20 games before you see some particular card for the first time. Of course you can still learn the game, but the process is very different and hence likely to attract different kind of players. Because of this observation, I have actually converged to saying that San Juan is better game than RftG (for me), because it feels much more friendly as a learning platform.