Appearence and tactics of early 5th century Saxons.

[Robert Vermaat]

Would it it true to say that Saxon troops of this period looked much the same as their Roman contemporaries, i.e. large oval shield, long slashing sword, ridge or spangenhelm style helmet, javelin and/or thrusting spear, usually unarmoured, long sleeved tunic, trousers with leg bindings?
And were they using similar tactics?

There's Saxons and there's Saxons.

Saxons as in from Germany and the Scandinavia would probably not use those weapons and use very different tactics.

Saxons as in from Britain would be a mix of Germanic migrants and (much more) Britons. Recent studies more and more agree that these 'migration hordes, carrying all before them and either killing or displacing the original British inhabitants', actually never happened. Now, some even go as far to flatly deny that there was any immigration to speak of, but that goes way to far for me.
However, the main point of these theories, being the uniterrupted continuity of rural sites all over southern and eastern Britain (the main areas where the Anglo-Saxons supposedly landed), is a strong argument in favour. Raping and killing invaders are extremely unlikely to continue the farms without even a break of a few years! It seems that economy changed, not the farmers.

My guess is that locally, elites changed from Roman or Romano-British to germanic newcomers, but that mostly, the Romano-Britons stayed where they were. Gradually they changed they ways they built their houses, clothing, jewellery, weapons, but much stayed the same, as it had since the pre-Roman Iron Age. Inhumation had continued to be used throughout Roman times, for instance.

So it seems that when the Roman influence waned from even the later 4th c. onwards, limited immigration brought new ideas and new fashions, which were taken up by the Britons during the 5th c. and onwards. Eventually the switched from Brythonic to Germanic languages.

So to answer your question, at first they would have looked much like the Late Ropmans, but they changed their way of warfare too (as they had done when the Romans arrived). But in all of that they will still have looked like Romans more than the saxons from northern Germany.