However, there is a compromise with ASoIaF. The series was originally designed as two trilogies separated by a five-year gap, but that was abandoned and the fourth volume (and elements of the fifth) was introduced to bridge that gap. However, although the gap is dead the first three books can still be read as a somewhat self-contained series. Book 3 ends with the characters 'plateaued' or left in interesting new situations but not on cliffhangers (as Book 4 ends). It is possible to read up to Book 3 and then go off and read something else. Whether you can do that or not is up to you: a lot of people find it impossible to resist moving straight onto Book 4, although it has a lot less closure than Book 3 (and I suspect Book 5 will have less still).
this is what worries me.
for the original poster's sake, i'll offer my thoughts as someone who hasn't read either series in completion.
WoT blew me away when i started. 'eye of the world' was exciting, mysterious, had tension, and got me hooked. there was a definite goal in mind... a showdown looming that provided ominous tension throughout. trying to fit the characters into ancient prophecies was fascinating.
however, people are right. around book 4-5, the series slipped. i couldn't finish book 6 and have never even tried to go back. it was a shame because prior to that, it was some of the best work i've ever read, fantasy or otherwise.
ASOIF... i just read the first book and was kind of underwhelmed. it wasn't bad, but i don't see what the fuss is about. at no point did it come close to the high points of wheel of time. there is no sense that any of the story will ever end. no showdowns in the making. no sense of any confrontation or resolution. it's like a long medieval soap opera. also, the alternating viewpoints can be frustrating, esp because some of the characters they center on are incredibly boring and do next to nothing the entire novel.
it was strangely addictive nonetheless, and part of me wants to continue on just to see what becomes of the characters i do like, but i can't skim books and the thought of reading through another chapter of dany riding a horse to nowhere to do nothing pains me.
the other worry is that martin says it's a 7-book series... now. i have read that jordan initially intended to make WoT a trilogy and you can somewhat sense that as things shift rapidly from book 3 to 4. it grew out of hand and he never finished. i have also heard that martin initially said ASOIF was supposed to be a trilogy or tetrology, then it was explanded to be 6 books. now i read 7 here. i fear i'll get sucked into yet another series with no end. and it'd be worse than jordan because at least jordan had his apoclayptic game-ender in mind. i don't think martin can ever put a lid on this series.
in short, WoT was wonderful... for a few books. then it tanked. it's up to you whether or not you can handle it. ASOIF, after one book, was a solid read, but as frustrating to me as it was enjoyable.
i'm moving on to read tad williams' MS&T before i return to martin. at least his series is finished.