Yeah, it all really comes down to how much you're willing to pay.
Which is why threads like these are becoming more prevalent, as the price line between universals and custom blurs. No longer is there a distinction between custom and universal in terms of *just* quality. Now, we have to distinguish between "low end" and "high end" custom.
The lowest prices custom is around like $130, am I right? I think the Sleek takes the cake for that. The highest price for a custom (that's well known) is the UE11, at nearly $1200. Between those prices lie a wealth of options for those looking to go custom. So many companies to consider. That's nearly $1000 of spread.
For universals, the spread is around half that, maybe even less. I'm not speaking from experience here, but I would imagine that the spread of quality across the universals is greater than the same spread across the custom market. All the earphones in question are using the same basic drivers (im not splitting hairs here), but when you eliminate variables like fit and isolation by going custom, you end up with reviews that focus more on SQ than over-all performance. For instance, say there are two universal earphones being reviewed. Earphone A gets great reviews on SQ, and earphone B has better reviews on comfort. If the difference is great enough, earphone B will be better rated because of its comfort level.
Now, take all that away because all customs will fit you the same, and generally have the same isolation. The differences come in SQ. So, by this logic, when you go custom, you're paying for better everything... fit, SQ, isolation... experience.
If it were me, I would go with the UE4. I don't think the extra driver of the TF10pro warrants the hassle of a universal, plus, since it's universal, you might sacrifice sound quality, making it comparable to a 2-driver, and thus, why not get a custom?