Oval is a bit different than other typical English wickets. It's faster, with good, true bounce and lightning fast out field. This is probably least toss influenced Test venue in UK, where better team of the day wins. Till day 2 morning, usual Oval track helps seemers and it'll always help express bowlers - but that doesn't mean one should bowl first always. If a batting unit can survive 1st 3 hours (2 hours on day 1 & 1st of Day 2), it's possible to post BIG scores, then spinners comes in to play as well. However, in dry summers, I have seen rank turning Oval wicket - sometimes in late 90s, that AUS side failed to chase 120 ish target against Caddick & Tufnel, Test ending probably in 3 days
I think, if they win toss, IND will like to bat first (though not sure how fit Ashwin is, they don't have a leggi, and Jadeja might not be effective on true Oval wicket). For ENG, it hardly matters - their top order seems to be good enough take them at 100/5 regardless of batting 1st or 2nd, then it's up to the bottom half. If they drop Adil for Woakes, I think they won't mind bowling first.
Either way, it's an ENG Test to lose - 4-1 for me. Normally, visitors often do well at Oval, because traditionally it's the last Test of summer and visitors by then are well acclimatized. Besides, Oval isn't a typical English seem friendly wicket, hence ENG doesn't enjoy the extra edge for their typical English condition seemers. Long back, I saw Neil Mallender ripping through PAK batting at Headingley, very next game he was bang average at Oval. Had this series been 3-1 for IND or even 2-2, I would have put them favorites at Oval, but not now.
Kohli was bitter disappointed at the end of 4th Test, and I hope one of the pacers don't break down after bowling for long on hard Oval landing surface. They have worked so hard and bowled well enough to lead at 3-1 by now, but in a dead rubber might loose heart. If bowlers don't out perform their usual once again, IND batting is not going to compete here - Oval will be high scoring game & no team with such tail can compete when new ball is taking 2/3 wickets before pacers are even sweating.
Still, there is no Dead rubber in Test, so the game will be entertaining, I'll definitely watch.