Rohitdev, these are two completely different animals. I have much more experience with the Cornwalls than with Tylers (PD-15s), but I will venture to guess that if you like one you probably won't like the other. You really need to find a pair of both speakers and take a good, long listen. Since Tyler Acoustics is an active concern, you should probably consult with a dealer regarding their products or an A'gon member with more experience than me.
A few words about the Cornwall: it's a great, classic speaker and they really rock! Macd says that his work great in his small room; maybe they do. My experience was not as good in my 10.5 x 13 room, even with moderate treatments. It's not that they didn't sound good, it's just that they were waaay too much speaker for the room. Maybe with a 2W amp you would be OK, but my with 12W SET it was not a good match. If you do elect to go with Cornwalls, I suggest late model Cornwall IIs and make sure that the crossovers are in good shape. You can buy repair kits or new crossovers here Critesspeakers.com
Another alternative in he Klipsch line might be the Heresy, Chorus or Forte speakers. Or the homebrewed and so-called CS-1 speakers (again, see Crites' web site). I have a pair of these and find they provide nearly the same midrange and top end as the Cornwall, but with significantly less bass response. They can be successfully used with a sub. If you are interested, drop me a PM and I'll hook you up with a friend that builds them and can answer any questions you might have.
If you are looking at Cornwalls you might also consider some of the Altec Lansing speakers that can provide similar performance. I have owned the Model 14, 15 and 17, and they all work pretty well in a smallish room. Although I really love the 604 driver used on the Model 17, the 14 works best in my room and that is what has stayed. They are big, but not as big as Cornwalls or the Tyler PDs. Great but controllable bass response, and the Mantaray horn can be tuned somewhat through careful application of damping material. Not necessarily a better sound than the Cornwall, but in my opinion it is more musical - smoother and less gritty.