I’ve gone through this exact decision-making process recently myself and in case it’s useful at all my thinking (or self-justification for buying a nicer toy!) was:
I’m a fairly competent DIY’er. For breaking sheet goods down I had made a guide for my circular saw out of plywood which worked as well as it could, but was a nightmare to clamp securely if what I was cutting was a lot shorter than my guide. Also, dust extraction was awful.
I considered the cheaper saws as I won’t use it all the time but, though I’ve bought a lot of cheaper tools in the past and been happy, I’ve often found that you need to fettle them in one way or another to make them work well, which in itself needs a level of technical competence or familiarity with that type of tool, neither of which in this regard I felt I had.
Also, as has been said above, the premium saws tend to have a very good resale value and (although in some ways this was very a part of the self-justification as I doubt I will ever sell it) it is always good to know that if you ever did need to get yourself out of financial hole you would be able to sell things and make something back. Also, I think you will often get a better future support for them if anything goes wrong (although some premium brands are known for better or worse after-care, I tend to find that if you don't have any joy with customer service, you will usually get a good result if you escalate to CEO-level with the premium brands)
This, combined with watching many reviews on YouTube (Peter Millard’s and Skilbuilder’s tracksaw showdown) as well as reading lots of forums led me to go for Makita as it seemed to be the best balance between quality/performance and price. Festool and Mafell did seem superior but were too much £ for me (and the difference not pronounced enough to make me dig deeper)
Initially, I was going to go for the corded SP6000J1 (around £280), as with a track saw you are always going to want to use dust extraction, so as soon as you’re plugged in to any sort of extraction device it makes cordless somewhat immaterial. However I am already bought in to the Makita 18v system and found that Screwfix had the cordless version DSP600 for £320 (including a Makpak box) which was considerably cheaper than anywhere else and actually was not that dissimilar to what some secondhand ones were going for on eBay. So, having used all that self-justification I bought the Makita and although it is my first track saw so I’m not comparing like for like, I am exceptionally happy with it and what it can achieve is mind-blowing.
For info, the cheapest (at the time) sources I found for the some of the bits you may want/need need with it were as below:
Saw- Screwfix £320
Joining bar to connect two rails together £13.95 Powertoolworld
1m guide rail £39.95 Powertoolworld
1.5m guide rail £55.15 ebay seller: buyaparcel
Pair of Makita guide rail clamps ebay seller: buyaparcel
Both buyaparcel items used a 15% off coupon (they often have ebay coupons for this seller)
I have recently bought a waste side jig and depth from Strawbyte workshop which was one of the most pleasant buying experiences I’ve ever had (and the cheapest postage ever)
Links to all above below (all will work with corded or cordless Makita other than the waste-side jig as the kerf is narrower on the cordless if my memory serves correctly)
Makita DSP600ZJ 36V Li-Ion LXT 165mm Brushless Cordless Plunge Saw - Bare
https://www.powertoolworld.co.uk/ma...joining-bar-connector-for-194368-5-sp6000-saw
https://www.powertoolworld.co.uk/makita-199140-0-1m-guide-rail-for-use-with-sp6000-dsp600-saws
Makita Aluminum Plunge Saw Guide Rail 1.5m 1500mm 59" SP6000 SP6000K1 199141-8 88381528689 | eBay
Makita 194385-5 Guide Rail Clamps For Plunge Saw SP6000 - 1 Pair 88381314084 | eBay
1.45mm Kerf Track Saw Guide - Waste-side Cut Jig (Pair) (Makita Efficut Blades) — The Strawbyte Workshop
Depth Stop Indicator for Makita Plunge Saws - SP6000J DSP600ZJ XPS01Z XPS02ZU — The Strawbyte Workshop