Actually, both chips are SAR A/Ds. Here is a sketchy comparison.
The TLV1504 is only 10 bits, vs. 12 bits for the ADS7841, for about the same price.
The speed is about the same for both. Of course, you can get the TLV2544 (12 bits), but it's more expensive.
ADS7841 has a simpler command set. On the other hand, wih the TLV1504 you get more features, plus the FIFO, which can come in handy.
SINAD is somewhat better for the ADS7841.
ADS7841 draws somewhat lower current.
The TLV1504 has a built-in reference, while the ADS7841 needs an external one (which costs more money).